Node directional neighbor discovery device and method for emergency rescue application

Abstract

The invention discloses a node directional neighbor discovery device and method for emergency rescue application, and belongs to the field of mine emergency rescue, and the device comprises a node carrying frame, a stepping motor, a connecting flange and a radiation isolation plate; the radiation isolation plate is of a V-shaped structure, the upper V-shaped end face is fixedly connected with the connecting flange, and the lower V-shaped end face is of an open structure. The node is provided with a rod-shaped omnidirectional antenna and extends into the internal space of the radiation isolation plate through the open structure of the lower V-shaped end surface of the radiation isolation plate; the motor drives the radiation isolation plate to rotate to realize formation and rotation of a directional wave beam; the method depends on the device and is operated inside the node, and directional discovery of the neighbor node is completed by aligning and rotating beams and receiving and sending data packets in different time intervals. The device and the method provided by the invention are simple and strong in expandability, and can improve the efficiency of discovering neighbor nodes by residual nodes after disasters and constructing an emergency communication network, thereby providing help for emergency rescue.

Description

Technical Field

[0001] The present invention belongs to the field of mine emergency rescue, and particularly relates to a node directional neighbor discovery device and method for emergency rescue applications. Background Art

[0002] Gas and roof accidents are prone to occur in coal mines. Along with them are the interruption of the roadway communication network and the entrapment of personnel. Using a wireless sensor network to reconnect the communication network after an accident and obtain accident information is an effective solution for emergency rescue. After an accident, the remaining wireless sensor network nodes are affected by the harsh environment, and the discovery of their neighbor nodes faces great challenges.

[0003] As a key link in network connectivity, the neighbor discovery of nodes is crucial. How to discover the surrounding surviving nodes and build communication links in the shortest possible time affects the efficiency of emergency rescue. Therefore, it is necessary to study efficient node discovery devices and methods applicable to gas and roof accidents in coal mine roadways. Summary of the Invention

[0004] The purpose of the present invention is to provide a node directional neighbor discovery device and method for emergency rescue applications, solve the problem of power loss in traditional node omnidirectional discovery, improve the directional discovery efficiency of nodes, and provide a key data transmission link for emergency rescue.

[0005] To achieve the above purpose, the present invention proposes a node directional neighbor discovery device and method for emergency rescue applications, and adopts the following technical solutions:

[0006] A node directional neighbor discovery device for emergency rescue applications, used for discovering neighbor nodes of residual wireless sensor network nodes underground. It is characterized by including a node mounting frame, a stepping motor, a connecting flange, and a radiation isolation plate; the node mounting frame is a three-sided hollow structure, the node is fixedly connected to the bottom surface of the node mounting frame, the stepping motor is fixed on the upper top surface of the node mounting frame, the output shaft of the stepping motor passes through the upper top surface and is connected to the connecting flange; the radiation isolation plate is a V-shaped structure, the upper V-shaped end face is fixedly connected to the connecting flange, and the lower V-shaped end face is an open structure; the node is configured with a rod-shaped omnidirectional antenna, which extends into the internal space of the radiation isolation plate through the open structure of the lower V-shaped end face of the radiation isolation plate to achieve directional selection of the radiation direction.

[0007] Further, the node mounting frame, the connecting flange, and the radiation isolation plate are formed by 3D printing. The node mounting frame and the connecting flange are made of resin materials, and the radiation isolation plate is made of aluminum alloy materials.

[0008] Further, the opening angle of the V-shaped structure of the radiation isolation plate is 60°.

[0009] Further, the specific operation process of the device is as follows: After the node that needs to discover neighbor nodes is powered on, the wireless communication module is activated to send and receive data packets. At the same time, the internal motor control program of the node periodically sends rotation commands to the stepper motor to drive the radiation isolation plate to rotate, thereby controlling the radiation direction of the rod antenna, achieving the aggregation of radiation energy, forming a directional radiation beam with a certain angular range, and efficiently discovering neighbors.

[0010] After an accident occurs underground, protected by the node protection device, some wireless sensor nodes remain intact and still have the ability of wireless communication. They are randomly distributed in the roadway accident environment. At the same time, due to the collapse of the rock mass at the top of the roadway, the nodes are covered by the collapsed coal and rock. In such a situation, the remaining nodes need to discover neighbors by themselves and build communication links. Therefore, the present invention also protects a method for directional neighbor discovery of nodes based on the above device, and adopts the following technical solutions:

[0011] A method for directional neighbor discovery of nodes for emergency rescue applications includes the following steps:

[0012] S1. The remaining nodes wake up the neighbor discovery function module, enter the neighbor search stage according to the preset search time, send wireless data packets in the preset communication mode, and sniff the received data packets to identify neighbor nodes;

[0013] S2. The motor drives the radiation isolation plate to rotate to form directional beams in all directions; within each directional beam, the following process is executed:

[0014] The remaining nodes judge whether the number of times of sending wireless data packets reaches the preset threshold through the neighbor discovery function module. If the preset threshold is reached, the search for neighbor nodes within the current directional beam ends, and the search for neighbor nodes within the next directional beam is entered; if the threshold is not reached, the search for neighbor nodes within the current directional beam range continues until the number of times of sending wireless data packets reaches the preset threshold;

[0015] S3. The remaining nodes judge whether the preset search time has been reached through the neighbor discovery function module. If the preset search time has been reached, all neighbor search tasks end. The nodes without neighbor search results continue to work in low power consumption, and the nodes with neighbor search results maintain continuous data communication with neighbor nodes; if the preset search time has not been reached, the neighbor node search task in S2 continues.

[0016] Further, the specific method for the remaining nodes to perform neighbor search tasks using the Zigbee communication method is as follows:

[0017] The remaining nodes are divided into coordinator nodes and end nodes, and different search steps are executed according to different types:

[0018] The remaining node A acts as a coordinator node. When entering the neighbor search phase, i.e., establishing a network, the stepper motor starts to work, driving the radiation isolation plate to rotate sequentially at a step angle of 60°, forming directional beams in various directions; within each directional beam, for a preset duration δ, the remaining node A records and analyzes the received data packets to obtain the ID information of neighbor nodes. If no data packets are received within the preset duration δ, it is determined that there are no neighbor nodes within the current directional beam angle range.

[0019] The remaining node B acts as a terminal node to search for a network or other terminal nodes. When entering the neighbor search phase, the stepper motor of the remaining node B starts to work, driving the radiation isolation plate to rotate sequentially at a step angle of 60°, forming directional beams in various directions; within each directional beam, the remaining node B executes tasks in two stages, maintaining preset durations δ1 and δ2 respectively; within the preset duration δ1, the remaining node B sends network detection data packets. If a network is detected, it will access the network and exchange data packets; within the preset duration δ2, the remaining node B broadcasts data packets and receives feedback data packets from other terminal nodes within the communication range, identifying and recording the information of neighbor nodes.

[0020] Furthermore, when using Bluetooth or LoRa communication methods, it is carried out according to the networking and communication rules, and the main differences from Zigbee are mainly reflected in the values and types of the preset time δ.

[0021] Furthermore, since the remaining nodes may be covered by coal and rock, and the electromagnetic signal will have losses when passing through the coal and rock medium, it is judged whether a data packet is received through the received signal strength (RSSI) threshold. When the directional beams of two nodes are aligned and the RSSI of the received data packet exceeds the preset threshold, it is determined that the node has discovered a neighbor node.

[0022] Furthermore, the implementation of the method requires the support of hardware, and the connection of its hardware circuit is as follows: the output end of the power supply is connected to the power supply end of the node core circuit board, and the core circuit board is connected to the power input end and signal input end of the motor control board, supplying power to the motor control board and sending control signals to it. The signal output end of the motor control board is connected to the stepper motor to control the rotation of the stepper motor, and the stepper motor is fixedly connected to the radiation isolation plate.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The present invention discloses a node directional neighbor discovery device and method for emergency rescue applications. Through the device design and program control of node directional neighbor discovery, it can effectively enable the remaining nodes after a disaster to efficiently discover neighbor nodes and construct an emergency communication link. The device realizes the formation, angle control and selection of node directional beam communication through mechanical means, with a simple method and strong scalability; the method derived from the device has strong program deployability. Description of the Drawings

[0025] Figure 1 The node directional neighbor discovery device provided by the present invention;

[0026] Figure 2 The principle of realizing the directional beam by the node directional neighbor discovery device provided by the present invention;

[0027] Figure 3 The operation process diagram of the device provided by the present invention;

[0028] Figure 4 The environment for the device provided by the present invention to perform node neighbor discovery;

[0029] Figure 5 The flow chart of the node directional neighbor discovery method based on the device provided by the present invention;

[0030] Figure 6 The node directional neighbor discovery method under the Zigbee communication mode in the present invention;

[0031] Figure 7 The hardware circuit connection diagram;

[0032] Explanation of the reference numerals in the figure: 1. Stepper motor, 2. Connecting flange, 3. Radiation isolation plate, 4. Node mounting frame, 5. Rod-shaped omnidirectional antenna, 6. Node. Detailed Embodiment

[0033] The technical solution of the present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0034] As Figure 1 shown, the present invention provides a node directional neighbor discovery device for emergency rescue applications, including a node mounting frame 4, a stepper motor 1, a connecting flange 2, and a radiation isolation plate 3; the node mounting frame 4 is a three-sided hollow structure, and the node 6 is fixedly connected to the bottom surface of the node mounting frame 4 by screws. The stepper motor 1 is fixedly mounted on the upper top surface of the node mounting frame 4, and its output shaft passes through the upper top surface of the node mounting frame 4 and is connected to the connecting flange 2 by interference fit; the radiation isolation plate 3 is a V-shaped structure, and screw holes are provided on the upper end surface of the V shape to realize the fixed connection with the connecting flange 2, and the lower V-shaped end surface is an open structure; the node 6 is configured with a rod-shaped omnidirectional antenna 5, and through the open structure of the lower V-shaped end surface of the radiation isolation plate 3, it extends into the internal space of the radiation isolation plate 3 to realize the directional selection of the radiation direction.

[0035] Figure 2 shows the principle of the device to realize the directional beam, Figure 2 (a) and (c) are the axial views of the rod-shaped antenna, and the circle represents the antenna; the radiation pattern of the traditional antenna is omnidirectional, asFigure 2 as shown in (b); Figure 2 The V-shaped structure in (c) plays a certain role in restricting the radiation direction and can achieve Figure 2 the directional beam at an angle α in (d). The angle α is related to the opening size of the V-shaped structure, and the opening angle of the V-shaped structure is 60°.

[0036] Figure 3 The operation process of the device is shown as follows: After the node that needs to perform neighbor discovery is powered on, the wireless communication module is started, continuously sending data packets and receiving data packets from other nodes at the same time; meanwhile, the motor control program is started, and the stepping motor drives the radiation isolation plate to rotate successively with a stepping angle of 60° to form directional radiation beams in different directions; when the beams of two nodes are aligned and the RSSI of the received data packet exceeds the set threshold, then it is determined that the node has discovered a neighbor node.

[0037] Figure 4 The environment for the node to perform neighbor discovery is shown as follows: After the underground roadway, the accident area is filled with collapsed coal and rock, as Figure 4 shown by the shaded part in it. The surviving nodes A, B, …, E run the node discovery program and discover the surrounding neighbor nodes by themselves according to the search steps corresponding to the node type. At any moment, the RSSIs of the data packets received while the beams of nodes A and B, and nodes D and E are aligned meet the threshold standard. Therefore, the two pairs of nodes have completed the node discovery work, while node C does not have a node whose beam is aligned with it at this moment and continues the discovery work at the next moment.

[0038] Figure 5 The flow chart of the node directional neighbor discovery method based on the above device is shown, including the following steps:

[0039] S1. The surviving node wakes up the neighbor discovery function module, enters the neighbor search stage according to the preset search time, sends wireless data packets in the Zigbee communication mode, and sniffs the received data packets to identify neighbor nodes;

[0040] S2. The motor drives the radiation isolation plate to rotate to form directional beams in each direction; within each directional beam, the following process is executed:

[0041] The surviving node judges whether the number of times of sending wireless data packets reaches the preset threshold through the neighbor discovery function module. If it reaches the preset threshold, the search for neighbor nodes within the current directional beam ends, and the search for neighbor nodes within the next directional beam enters; if it does not reach the threshold, the search for neighbor nodes within the current directional beam range continues until the number of times of sending wireless data packets reaches the preset threshold;

[0042] S3. The remaining nodes determine whether the preset search time has been reached through the neighbor discovery function module. If the preset search time has been reached, all neighbor search tasks are terminated. Nodes without neighbor search results continue to operate in low power consumption, and nodes with neighbor search results maintain continuous data communication with neighbor nodes. If the preset search time has not been reached, the neighbor node search task in S2 continues.

[0043] Figure 6 The following shows the specific method of the neighbor search program in the Zigbee communication mode: The remaining node A as the coordinator establishes a network when powered on. The stepper motor drives the radiation isolation plate to rotate in steps of 60° to form directional beams in different directions, maintains the preset duration δ within each directional beam, and sends and receives data packets until neighbors are found. The remaining node B as the end node sends network detection data packets at the preset duration δ1 to find existing networks, broadcasts data packets within the preset duration δ2 to find other end nodes within the communication range, and drives the radiation isolation plate to rotate through the stepper motor to sequentially switch the beam directions until the search task within the preset time is completed.

[0044] Figure 7 The following shows the connection of the hardware circuit: The power module is connected to the power supply terminal of the CC2530 main control chip. The four signal output terminals of the CC2530 are connected to the signal input terminals of the motor control board and also to its power input terminal to provide power supply. The signal output terminal of the motor control board is connected to the signal input terminal of the stepper motor to control the rotation of the stepper motor, and the stepper motor is fixedly connected to the radiation isolation plate.

[0045] The above is only the preferred specific implementation manner of the present invention and is not used to limit the present invention. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the technical scope disclosed by the present invention according to the technical solution and inventive concept of the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A node-oriented neighbor discovery device for emergency rescue applications, used for discovering neighbor nodes of wireless sensor network nodes remaining underground, characterized in that: It includes a node mounting frame, a stepper motor, a connecting flange and a radiation isolation plate; the node mounting frame is a three-sided hollow structure, the node is fixedly connected to the bottom surface of the node mounting frame, the stepper motor is fixed to the upper top surface of the node mounting frame, the stepper motor output shaft passes through the upper top surface and is connected to the connecting flange; the radiation isolation plate is a V-shaped structure, the upper V-shaped end face is fixedly connected to the connecting flange, and the lower V-shaped end face is an open structure; the node is equipped with a rod-shaped omnidirectional antenna, which extends into the internal space of the radiation isolation plate through the open structure of the lower V-shaped end face of the radiation isolation plate to achieve directional selection of the radiation direction.

2. A node-oriented neighbor discovery device for emergency rescue applications according to claim 1, characterized in that: The node mounting frame, connecting flange and radiation isolation plate are formed by 3D printing technology; the node mounting frame and connecting flange are made of resin material, and the radiation isolation plate is made of aluminum alloy material.

3. A node-oriented neighbor discovery device for emergency rescue applications according to claim 2, characterized in that: The opening angle of the V-shaped structure of the radiation isolation panel is 60°.

4. A node-oriented neighbor discovery device for emergency rescue applications according to claim 1, characterized in that: The operation process of the device is as follows: after the node that needs to discover neighbor nodes is powered on, its wireless communication module is started to send and receive wireless data packets; at the same time, the internal motor control program of the node regularly sends rotation instructions to the stepper motor, driving the radiation isolation plate to rotate, controlling the radiation direction of the rod antenna, and forming directional beams in different directions.

5. A node-directed neighbor discovery method based on the node-directed neighbor discovery device for emergency rescue applications as claimed in claim 1, characterized in that: The following steps are involved: S1, the surviving node wakes up the neighbor discovery function module, enters the neighbor search phase according to the preset search time, sends wireless data packets in a preset communication mode, sniffs the received data packets, and identifies the neighbor nodes; S2. The motor drives the radiation isolation plate to rotate to form directional beams in all directions. In each directional beam, the following process is performed: The surviving nodes use the neighbor discovery function module to determine whether the number of wireless data packets sent reaches a preset threshold. If the preset threshold is reached, the neighbor node search in the current directional beam is terminated and the neighbor node search in the next directional beam is started. If the threshold is not reached, the neighbor node search in the current directional beam is continued until the number of wireless data packets sent reaches the preset threshold. S3. The surviving nodes determine whether the preset search time has been reached through the neighbor discovery function module. If the preset search time has been reached, all neighbor search tasks are terminated, and the nodes without neighbor search results continue to maintain low power operation, and the nodes with neighbor search results maintain continuous data communication with neighbor nodes; if the preset search time has not been reached, the neighbor node search task of S2 is continued.

6. The node-directed neighbor discovery method according to claim 5, characterized in that: The surviving nodes use Zigbee communication to search for neighbors. The surviving nodes are divided into coordinator nodes and terminal nodes. Different search steps are performed according to different types, specifically: The surviving node A acts as a coordinator node. When it enters the neighbor search phase, i.e., establishing a network, the stepper motor starts working, driving the radiation isolation plate to rotate in steps of 60° in sequence, forming directional beams in all directions. In each directional beam, the preset duration δ is maintained, and the surviving node A records and parses the received data packets to obtain the ID information of the neighbor nodes. If no data packets are received within the preset duration δ, it is determined that there are no neighbor nodes within the current directional beam angle range. The surviving node B acts as a terminal node to search for the network or other terminal nodes. When entering the neighbor search phase, the stepper motor of the surviving node B starts to work, driving the radiation isolation plate to rotate in 60° steps to form directional beams in all directions. In each directional beam, the surviving node B performs tasks in two stages, maintaining the preset durations δ1 and δ2 respectively. Within the preset time δ1, the surviving node B sends a network detection data packet. If the network is detected, it will enter the network and exchange data packets; Within the preset time length δ2, the surviving node B broadcasts a data packet, receives feedback data packets from other terminal nodes within the communication range, and identifies and records the information of the neighboring nodes.

7. The node-directed neighbor discovery method according to claim 6, characterized in that: When the directional beams of the two nodes are aligned and the RSSI of the received data packet exceeds the preset threshold, it is determined that the node has discovered the neighbor node.

8. The node-directed neighbor discovery method according to claim 7, characterized in that: The connection of the hardware circuit for implementing the node-directed neighbor discovery method is as follows: the output end of the power supply is connected to the power supply end of the node core circuit board, the core circuit board is connected to the power input end and the signal input end of the motor control board, the motor control board is powered and sends a control signal to it, the signal output end of the motor control board is connected to the stepper motor to control the rotation of the stepper motor, and the stepper motor is fixedly connected to the radiation isolation board.

Images