KR101021125B1 - Method for moving of mobile node, mobile node and moving apparatus - Google Patents

Abstract

The present invention relates to a method of moving a mobile node, a mobile node and a mobile device. According to an aspect of the present invention, a method of moving a plurality of mobile nodes in a sensor network is disclosed. According to an embodiment of the present invention, a method of moving a mobile node includes a) moving a first mobile node in a moving state according to a predetermined path and a target point, and b) broadcasting the distance information request message by the first mobile node. C) receiving, by the first mobile node, a response message including distance information from the second mobile node in a stopped state; and d) the first mobile node arriving at the target point using the distance information. It includes a step.

Sensor network, node, distance

Description

Mobile node movement method, mobile node and mobile device {METHOD FOR MOVING OF MOBILE NODE, MOBILE NODE AND MOVING APPARATUS}

The present invention relates to a method of moving a mobile node, a mobile node, and a mobile device, and more particularly, to a mobile node used in a sensor network.

Recently, many applications such as environmental monitoring, intrusion prevention, and object tracking using sensor network technology have been developed. It is important that such applications find location information of sensor devices every week. The application itself may require location information. However, the location information of the sensor device is also useful for network operation.

When transmitting data to a sensor device that collects data, if the location information of the sensor device is known, efficient delivery is possible. After configuring the sensor network, location information of many sensor devices is needed for maintenance, such as the placement of additional sensor devices. Positioning of many sensor devices is required for good positioning.

There are three considerations when constructing a sensor network. Considerations are the sensing coverage to collect all the environmental information of the area of interest, the communication distance to construct the wireless network, and the sufficient distance information to measure the location.

The number of sensor devices is determined by the ranging range of the sensor device having the shortest ranging range among the sensor devices. In other words, the sensor devices must be within the distance measurement range to allow distance measurement. Therefore, the shorter the distance measurement range, the more the number of sensor devices present in the sensor network increases.

 In addition, according to the prior art, there is a technique for measuring the distance using one robot. However, the prior art has a problem in that, when using a sensor device having a relatively short distance measuring range, many sensor devices must also be arranged. In addition, the prior art has a problem that by using one robot, the movement time is increased by the inefficient movement of the robot, thereby increasing the time for measuring the position.

An object of the present invention is to efficiently move a plurality of mobile nodes for the position measurement of sensor nodes in a sensor network.

According to an aspect of the present invention, a method of moving a plurality of mobile nodes in a sensor network is disclosed.

According to an embodiment of the present invention, a method of moving a mobile node includes a) moving a first mobile node in a moving state according to a predetermined path and a target point, and b) broadcasting the distance information request message by the first mobile node. C) receiving, by the first mobile node, a response message including distance information from the second mobile node in a stopped state; and d) the first mobile node arriving at the target point using the distance information. It includes a step.

Here, after step d), e) the first mobile node arrives at the target point and broadcasts location information, f) the second mobile node receives and stores the location information, and g) Changing the second mobile node from the stopped state to the mobile state and repeating steps a) to f).

Here, in step c), the second mobile node measures the distance to the first mobile node and transmits the distance information to the first mobile node.

Here, in step d), when the distance information is less than a preset threshold, the first mobile node determines that the target location has been reached.

Here, step c) includes the step of receiving a response message including distance information from the third mobile node in a state where the first mobile node is stationary, and the step f) includes: Receiving and storing the location information, the step g) comprises the step of changing the third mobile node from the stationary state to the moving state to repeat the steps a) to f).

Here, the first to third moving nodes are moved while maintaining the arrangement of the equilateral triangle with the distance measuring range as one side.

Here, one of the first to third mobile nodes is in a moving state at a time, and the remaining mobile nodes are in a stopped state.

In accordance with another aspect of the present invention, a mobile node is disclosed in a sensor network.

The mobile node according to an embodiment of the present invention measures a distance from another mobile node requesting distance information using a sensor, and generates a distance information between the mobile nodes and a distance information request message with the other mobile node. Or a communication unit configured to transmit and receive a response message including the distance information.

Here, the distance measuring unit measures the distance using an RF signal and an ultrasonic wave.

According to another aspect of the present invention, a mobile device is disclosed that is coupled to a mobile node in a sensor network to move the mobile node.

A mobile device according to an embodiment of the present invention controls the driving unit to move while maintaining a predetermined distance from another mobile node by using a traveling unit that performs movement with respect to the mobile device and distance information measured by the mobile node. It includes a control unit.

Herein, the control unit controls the movement according to a preset route and a target point, and controls the movement to maintain the distance with the other moving node below a distance measurement range.

Here, the other mobile node has two mobile nodes, and the control unit controls the movement so that the three mobile nodes maintain the arrangement of the equilateral triangle with the distance measuring range as one side.

The present invention has the effect that a plurality of mobile nodes can be moved efficiently for the position measurement of the sensor node in the sensor network.

In addition, the present invention has the effect of reducing the number of fixed sensor nodes by using a plurality of mobile nodes in the sensor network.

In addition, the present invention has the effect of reducing the position measurement time by moving a plurality of mobile nodes in the sensor network efficiently.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view for explaining a method of moving a mobile sensor node in a sensor network according to an embodiment of the present invention. In more detail, FIG. 1 is a diagram for describing a relationship between sensor nodes in a sensor network. The sensor nodes configured in the sensor network according to the present invention may include mobile sensor nodes 10-1, 10-2, and 10-3 and fixed sensor nodes 20-1 and 20-2.

Referring to FIG. 1, the sensor network includes mobile sensor nodes 10-1, 10-2, 10-3 and fixed sensor nodes 20-1, 20-2. In FIG. 1, a limited number of mobile sensor nodes 10-1, 10-2, and 10-3 and fixed sensor nodes 20-1 and 20-2 are shown. It will be apparent to those skilled in the art that the number of nodes may vary.

The movement sensor nodes 10-1, 10-2, and 10-3 move toward the final target point along the preset movement path 30. Each of the mobile sensor nodes 10-1, 10-2, and 10-3 may move to a predetermined target point one at a time. Methods of moving the three mobile sensor nodes 10-1, 10-2, and 10-3 will be described later in detail with reference to FIGS. 4 to 6.

The mobile sensor nodes 10-1, 10-2, and 10-3 may move while maintaining a distance ranging range (RD). For example, the mobile sensor nodes 10-1, 10-2, and 10-3 are initially arranged in an equilateral triangle shape having a distance measuring range on one side, and can move while maintaining the equilateral triangle shape.

The ranging range is the maximum distance that the ranging sensor mounted on the mobile sensor node can measure. Although the distance measuring range has a predetermined distance measuring range for each distance measuring sensor used, it will be described on the assumption that the same distance measuring sensor is used in the present invention. The mobile sensor nodes 10-1, 10-2, and 10-3 and the fixed sensor nodes 20-1 and 20-2 may be located within each other in the distance measuring range to measure the distance.

Referring back to FIG. 1, the fixed sensor nodes 20-1 and 20-2 are located outside of the distance measurement range. The mobile sensor nodes 10-1, 10-2, and 10-3 move along the movement path 30 between the fixed sensor nodes 20-1 and 20-2.

When the mobile sensor nodes 10-1, 10-2, and 10-3 move and are located at positions 11-1, 11-2, and 11-3, respectively, the number 11-1 mobile sensor nodes are numbered 20-1. It is included in the range of the fixed sensor node and the range, and the mobile sensor node 11-2 is included in the range range outside the 20-2 fixed sensor node.

Therefore, when measuring the distance between 20-1 fixed sensor node and 20-2 fixed sensor node, the 20-1, 11-1, 11-2 and 20-2 sensor nodes are measured with each other You can measure the distance by being in range.

The mobile sensor nodes 10-1, 10-2, and 10-3 move between fixed sensor nodes 20-1 and 20-2, which are not included in the distance measurement range, within the sensor network. It can be measured.

2 is a block diagram showing a mobile sensor node 10 according to an embodiment of the present invention.

Referring to FIG. 2, the mobile sensor node 20 includes a mobile node 100 and a mobile device 200. The mobile node 100 may include a component for measuring a distance from another mobile node or the fixed sensor nodes 20-1 and 20-2. The mobile device 200 may move between the fixed sensor nodes 20-1 and 20-2 according to a preset path in the sensor network. The mobile device 200 is combined with the mobile node 100 to move the mobile node 100.

The mobile node 100 includes a communication unit 110 and a distance measuring unit 120.

The communication unit 110 may transmit / receive data with another mobile node 100 or the fixed sensor nodes 20-1 and 20-2. For example, the communication unit 110 may transmit and receive a distance measurement request message, a response message including distance measurement information, location information, and the like.

The communication unit 110 may be provided in all sensor nodes, and may process data transmitted and received between the sensor nodes.

The distance measuring unit 120 measures a distance from another sensor node using a distance measuring sensor. The distance measuring unit 120 may perform distance measurement according to a distance measurement request message of another mobile node received through the communication unit 110. The distance measuring unit 120 may measure a distance by using a radio frequency (RF) signal and ultrasound.

The measured distance may be used to calculate relative position information of each sensor node based on any sensor node. In addition, the measured distance may be used to calculate absolute position information of each sensor node when absolute position information (for example, geographical position) of the sensor node as a reference is measured.

The moving device 200 includes a control unit 210 and a driving unit 220. The mobile device 200 according to the present invention may be a robot operating according to a preset algorithm. In addition, the mobile sensor node 10 including the mobile node 100 and the mobile device 200 may be a robot having a position measuring function.

The controller 210 controls the driving unit 220 to move the mobile device 200 according to a preset algorithm or a moving method.

The control unit 210 controls to move according to a predetermined movement path, and controls to move while maintaining a constant distance from another moving node. The controller 210 controls the mobile node 100 to move to a predetermined target point without departing from the distance measurement range by using the distance information measured by the mobile node 100.

For example, when three moving nodes 100 exist, the control unit 210 maintains an equilateral triangle shape in which the three moving nodes 100 have a distance measuring range on one side, and moves along a preset movement path. Can be controlled.

The driving unit 220 performs a movement with respect to the mobile device under the control of the controller 210. The driving unit 220 may be a moving means including a motor, a wheel, and the like, and may be a moving means of a robot that moves according to a preset algorithm.

3 is a flowchart illustrating a method of moving a mobile sensor node 10 in a sensor network according to an embodiment of the present invention. Here, the mobile sensor node 10 is a form in which the mobile device 200 is added to the mobile node 100, the mobile device 200 controls the actual movement, hereinafter, to facilitate the understanding of the present invention, the mobile node ( It describes with the moving method of 100).

The movement method of the mobile node 100 according to the present invention is assumed to use three mobile nodes 100, but is not limited thereto.

Referring to FIG. 3, the first to third mobile nodes 100 are arranged to be kept at a predetermined distance from each other, and a path and a target point are set at step S310. The first to third moving nodes 100 may be arranged in an equilateral triangle shape having a distance measuring range as one side. The path may be set in a straight line between the fixed sensor nodes 20-1 and 20-2 in the sensor network.

Next, the first mobile node 100 moves toward the preset target point, and the remaining second and third mobile nodes 100 are in a stopped state (S320). Here, the first mobile node 100 is in a moving state, and the second and third mobile nodes 100 are in a stationary state. Here, the first to third numbers are used to determine the order of the mobile node for the purpose of understanding the present invention, and the state may be changed regardless of the order. In the moving method of the mobile node 100 according to the present invention, if any one of the three mobile nodes 100 is in the moving state, the other two mobile nodes 100 are in the stopped state. That is, the three mobile nodes 100 move along the movement path, but one mobile node 100 moves at a time. After one mobile node 100 completes the movement, the other mobile node 100 may move in a preset order.

Next, the first mobile node 100 broadcasts a request message to the remaining mobile node 100 (S330). The request message is a distance measurement request message and is a message for requesting distance measurement between the requested first mobile node 100 and the remaining mobile nodes 100.

Next, when receiving the request message of the first mobile node 100, the second and third mobile node 100 performs a distance measurement (S340). The second and third mobile nodes 100 measure distances to the first mobile node 100 broadcasting the request message. In this case, the second and third mobile nodes 100 may measure a distance by using a radio frequency (RF) signal and an ultrasonic wave.

Next, the first mobile node 100 receives a response message including distance information from the second and third mobile nodes 100 (S350).

Next, the first mobile node 100 arrives at the target point (S360). The first mobile node 100 may arrive at a predetermined target point using distance information received from the second and third mobile nodes 100. When the distance information is less than a preset threshold, the first mobile node 100 may determine that the target point has arrived. The threshold may be a ranging range. The first moving node 100 may move to the target point by setting the distance measuring range as the maximum moving distance. The first mobile node 100 may move to a target point and move to a point not exceeding the distance measurement range with the second and third mobile nodes.

Next, the first mobile node 100 arriving at the target point broadcasts the location information (S370). The location information may be relative location information or absolute location information of the first mobile node 100. The relative position information may be distance information from the mobile node 100 as a reference. The mobile node 100 serving as a reference may be set in advance and measure absolute position information. According to the mobile node 100 as a reference, the first mobile node 100 may calculate absolute location information using distance information.

Next, the second and third mobile nodes 100 store location information of the first mobile node (S380). The second and third mobile nodes 100 may calculate distances that can be moved using the stored location information of the first mobile node.

Next, when the first mobile node is in the stopped state, the second and third mobile nodes are sequentially moved to repeat the procedure performed by the first mobile node (S390).

The first to third mobile nodes 100 may alternately move along a predetermined path. At this time, the moving distance of each mobile node 100 may be determined under the condition of maintaining the distance measuring range with the remaining mobile node 100.

Hereinafter, the moving method and arrangement of the three mobile nodes 100 will be described in detail with reference to FIGS. 4 to 6.

4 is a view showing a moving method of the mobile node 100 according to an embodiment of the present invention, Figure 5 is a view for explaining the maximum moving distance of the mobile node 100 according to an embodiment of the present invention. 6 is a view for explaining the arrangement of the mobile node 100 according to an embodiment of the present invention. The same reference numerals are given to the same components, but the mobile nodes 1, 2, and 3 of FIGS. 4 to 6 will be described with new reference numerals for the purpose of understanding the present invention.

Referring to FIG. 4, the moving nodes 1, 2, 3 are initially arranged keeping the distance measuring range. The moving nodes 1 to 3 maintain an equilateral triangle shape with one side of the distance measuring range.

First, the moving node 1 moves to the moving node 3 direction. The maximum moving distance of the first moving node may be a distance measuring range. However, since the location of the third mobile node is located at the maximum moving distance, the first mobile node can move closest to the third mobile node.

Next, the second moving node moves in the direction indicated by the arrow. Also, the maximum moving distance of the second mobile node may be a distance measuring range. In this case, the second mobile node may move to a distance not exceeding the distance measurement range with the first mobile node.

 Next, the moving node 3 moves in the direction of travel indicated by the arrow. The moving node 3 may move to the moving node 1 and the moving node 2 to the point where the distance measuring range is maximized.

As such, the moving nodes 1 to 3 may alternately move each other repeatedly.

Referring to FIG. 5, the moving nodes 2 and 3 are included in the distance measurement range. The circled dotted line indicates the range of measurement for each mobile node. The location of the first mobile node may be determined as a portion where the circles of the second and third mobile nodes overlap. That is, the second mobile node may be located at the x point. The moving node 2 can move by the distance measuring range. The reason for this is that when the straight line is moved from an isosceles triangle having one side as the distance measuring range, the maximum moving distance of the second moving node cannot exceed the distance measuring range.

Referring to FIG. 6, FIG. 6 shows that when the first to third mobile nodes are arranged in an equilateral triangle shape, the most effective arrangement is made. The distance measurement range of the mobile node 3 may be represented by an arc indicated by a dotted line. If the location of mobile node 1 is within the distance measurement range of mobile node 3 and the x position maintains the distance measurement range with mobile node 2, the maximum travel distance of mobile node 2 is defined as mobile node 2 and 3. It is limited to the connected line segment (arrow direction).

In order to increase the maximum moving distance of mobile node 1, first, mobile node 1 must be located at y position away from the moving node 2 and 3 by the distance measuring range. In this case, although the maximum moving distance of the first moving node is increased, the maximum moving distance does not become the distance measuring range.

When the first mobile node is located at the a position and the second mobile node is located at the b position, the first to third mobile nodes maintain the distance measuring range with each other, and the first mobile node can move by the distance measuring range. Therefore, the arrangement form of the moving nodes 1 to 3 is an equilateral triangle in which the length of one side is a distance measuring range.

The method for moving a mobile node according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. Computer-readable media may include, alone or in combination with the program instructions, data files, data structures, and the like.

The program instructions recorded on the computer readable medium may be those specially designed and constructed for the present invention, or may be known and available to those skilled in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, such as floppy disks. Hardware devices specially configured to store and execute program instructions such as magneto-optical media and ROM, RAM, flash memory and the like. In addition, the above-described medium may be a transmission medium such as an optical or metal wire, a waveguide, or the like including a carrier wave for transmitting a signal specifying a program command, a data structure, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like.

The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be understood that the invention may be varied and varied without departing from the scope of the invention.

1 is a view for explaining a method of moving a mobile sensor node in a sensor network according to an embodiment of the present invention.

2 is a block diagram showing a mobile sensor node 10 according to an embodiment of the present invention.

3 is a flowchart illustrating a method of moving a mobile sensor node 10 in a sensor network according to an embodiment of the present invention.

4 is a view showing a method of moving a mobile node 100 according to an embodiment of the present invention.

5 is a view for explaining the maximum moving distance of the mobile node 100 according to an embodiment of the present invention.

6 is a view for explaining the arrangement of the mobile node 100 according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: mobile sensor node 100: mobile node

200: moving device

Claims (12)

In the method of moving a plurality of mobile nodes in the sensor network, a) moving the first mobile node in a moving state according to a predetermined path and a target point; b) the first mobile node broadcasting a distance information request message; c) receiving, by the first mobile node, a response message including distance information on the relative distance between the mobile nodes from the second mobile node in the stopped state; And and d) reaching the target point by the first mobile node maintaining the distance below the distance measurement range with another mobile node using the distance information. The method of claim 1, After step d), e) the first mobile node arriving at the target point and broadcasting location information; f) receiving and storing the location information by the second mobile node; and and g) changing the second mobile node from the stationary state to a mobile state, and repeating steps a) to f). The method of claim 1, In step c), And the second mobile node measures the distance to the first mobile node and transmits the distance information to the first mobile node. The method of claim 1, In step d), And the first mobile node determines to arrive at the target point when the distance information is less than the distance measurement range. The method of claim 2, C), Receiving, by the first mobile node, a response message including distance information from the third mobile node in the stopped state, F) step, Receiving and storing, by the third mobile node, the location information; Step g), And repeating the steps a) to f) by changing the third mobile node from the stationary state to the mobile state. The method of claim 5, And the first to third moving nodes are arranged in an equilateral triangle having a distance measuring range as one side, and are moved while maintaining a distance between each other below the distance measuring range. The method of claim 5, Wherein the first to third mobile nodes are in a mobile state at a time, and the remaining mobile nodes are in a stopped state. For mobile node in sensor network, A distance measuring unit generating distance information between mobile nodes by measuring a distance from another mobile node requesting distance information using a sensor; And Includes a communication unit for transmitting and receiving a distance information request message or a response message including the distance information with the other mobile node, The mobile node is moved by maintaining a distance of less than the distance measurement range to the other mobile node by using the distance information by the coupled mobile device. The method of claim 8, The distance measuring unit is a mobile node, characterized in that for measuring the distance by using a radio frequency (RF) signal and ultrasonic (Ultrasound). In the mobile device coupled to the mobile node in the sensor network to move the mobile node, A driving unit which performs a movement with respect to the moving device; And And a controller configured to control the driving unit to move while maintaining a distance below a distance measurement range with another mobile node by using the distance information measured by the mobile node. The method of claim 10, The control unit is characterized in that for controlling the movement in accordance with a predetermined path and the target point. The method of claim 11, The other mobile node has two mobile nodes, And the control unit controls the movement so that the three moving nodes maintain the arrangement of the equilateral triangle with the distance measuring range as one side.

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