JP6673495B2 - Control device, control system and control method - Google Patents

Description

  The present invention relates to a control device, a control system, and a control method.

  In recent years, for example, sensor nodes (hereinafter simply referred to as nodes) are scattered over sensing objects such as cliffs, roads, and buildings, and the state of the sensing objects is collected by wireless communication through each node. It has been known. The observation device in the WSNS collects the state detected by each node, and recognizes the state of the sensing target based on the collected result.

  For example, when each node performs environmental power generation using a solar cell, the amount of power stored in the secondary battery of each node changes according to the environment such as weather. Therefore, each node performs an operation according to the amount of stored power.

JP 2012-063907 A JP 2013-027164 A JP 2012080622 A JP-A-2015-122572

  However, even when the node does not perform the measurement operation, the secondary battery of the node may be empty due to spontaneous discharge, leakage current of the power supply circuit, or the like. Such a node is activated when the power storage environment is prepared, and performs a connection attempt to a nearby node. Each node also consumes power during this connection attempt, so the secondary battery of the node runs out at night, and the connection attempt cannot be performed at night or in bad weather.

  An object of one aspect is to provide a control device or the like that can efficiently perform connection setting between nodes.

  In one case, the control device includes a communication unit, a determination unit, and a sleep instruction unit. The communication unit receives information from the first node using multi-hop communication between a plurality of nodes including a connected first node and an unconnected second node. The determining unit includes: a remaining battery level of the first node; a communication quality between the first node and the second node; a power characteristic of the second node; The first node determines an acceptance date and time at which the first node accepts a connection with the second node, based on first environment information on an environment at a position where is located. The sleep instruction unit instructs the first node to put the first node into a sleep state until the reception date and time.

  In one aspect, connection setting between nodes can be performed efficiently.

FIG. 1 is an explanatory diagram illustrating an example of the control system according to the present embodiment. FIG. 2 is a diagram illustrating an example of a node. FIG. 3 is a diagram illustrating an example of the control device. FIG. 4 is a block diagram illustrating a functional configuration example of a node. FIG. 5 is a block diagram illustrating a functional configuration example of the control device. FIG. 6 is a flowchart illustrating an example of a processing operation when the node is started. FIG. 7 is a flowchart illustrating an example of a processing operation of the node in a reception standby state. FIG. 8 is a flowchart illustrating an example of a processing operation in a standby state of the control device. FIG. 9 is a diagram illustrating a configuration example of unconnected node information. FIG. 10 is a diagram illustrating a configuration example of the connection node information. FIG. 11 is a flowchart illustrating an example of the update processing operation of the control device. FIG. 12 is a diagram illustrating a configuration example of the environment information. FIG. 13 is a diagram for explaining an example of the route selection method. FIG. 14 is a flowchart illustrating an example of the sleep processing operation of the control device. FIG. 15 is a flowchart illustrating an example of a post-accepting processing operation of the control device.

  Hereinafter, embodiments of a control device, a control system, and a control method disclosed in the present application will be described in detail with reference to the drawings. Note that the disclosed technology is not limited by the present embodiment. Further, the respective embodiments described below may be appropriately combined within a range that does not cause inconsistency.

  FIG. 1 is an explanatory diagram illustrating an example of the control system 1 according to the present embodiment. The control system 1 shown in FIG. 1 is a sensor system that collects information measured using a sensor via a network. The control system 1 is configured by, for example, a WSNS (Wireless Sensor Network System), and includes a plurality of nodes 2, a gateway (GW) 3, and the Internet 4. The node 2 and the GW 3 are connected by a multi-hop wireless network using multi-hop communication (also called ad-hoc communication). The GW 3 of the control system 1 collects information measured by each node 2.

  The node 2, which is a sensor node, is scattered and arranged on a sensing target such as a cliff, a road, a structure, or the like, and detects a state of the sensing target. The node 2 wirelessly communicates with another node 2 in the control system 1 using multi-hop communication. Each node 2 has, for example, a parent-child connection relationship, and wirelessly communicates with other nodes 2 within a predetermined area by multi-hop communication. In each node 2, a parent node on the upper side and a child node on the lower side are connected in a tree structure.

  The GW 3 is a communication device that is communicatively connected to the node 2, and is an example of a control device 300 described later. The GW 3 connects to the node 2 using multi-hop communication. The GW 3 is directly connected to the node 2 in the predetermined area, and is connected to the other nodes 2 through one or more nodes 2. The GW 3 is connected to the Internet 4 via a cable or a mobile phone network. The GW 3 uses the Internet 4 to acquire environment information 5 indicating information about the environment of the place where the node 2 is located, and controls the node 2 using the acquired environment information 5. The GW 3 controls the operation state of the node 2 using the state and characteristics of the node 2. The GW 3 causes the node 2 to transition to a sleep state or a normal operation state, for example. The GW 3 controls the operation state of the node 2 by transmitting the sleep date and time and the activation date and time to the node 2. The GW 3 collects information obtained by the node 2 using a sensor or the like via multi-hop communication between the nodes 2 and transmits the collected data to a server or the like via the Internet 4.

  In the control system 1 shown in FIG. 1, for example, when the node 2 of “E” and “F” is a child node, the node 2 of “D” is a parent node of “E” and “F”, and the node “D” If the node 2 of “A” is a child node, the node 2 of “A” is the parent node of “D”. Further, for example, when the node 2 of “G” and “H” is a child node, the node 2 of “C” is a parent node of “G” and “H”, and the node 2 of “C” is a child node. In this case, the node 2 of “A” is set as the parent node of “C”. Further, when the node 2 of “I” and “J” is a child node, the node 2 of “B” is a parent node of “I” and “J”. The GW 3 is wirelessly connected to the nodes “A” and “B”. Further, the GW 3 makes a communication connection to the Internet 4. The GW 3 may be connected to a communication line other than the Internet 4.

  FIG. 2 is a diagram illustrating an example of the node 2. FIG. 2 illustrates a hardware configuration example of the node 2. The node 2 includes an information processing unit 20, an energy harvesting element 21, a power control unit 22, and a secondary battery 23. The information processing unit 20 includes an MCU (Micro Controller Unit) 24, a RAM (Random Access Memory) 25, a ROM (Read Only Memory) 26, a sensor 27, and a wireless unit 28.

  In the node 2, the power control unit 22 is connected to the information processing unit 20, the energy harvesting element 21, and the secondary battery 23. In the information processing unit 20, the MCU 24, the RAM 25, the ROM 26, the sensor 27, and the wireless unit 28 are connected by a bus or the like.

  The energy harvesting element 21 is, for example, a power generation element such as a vibration power generation element, a photovoltaic power generation element, a temperature power generation element, or a radio wave power generation element. When the energy harvesting element 21 is an electricity generating element such as a solar cell, the energy harvesting element 21 generates power using sunlight. The energy harvesting element 21 sends the generated power to the power control unit 22. The energy harvesting element 21 is also called an energy harvesting element. The secondary battery 23 is, for example, a battery that stores power generated by the energy harvesting element 21. Note that the secondary battery 23 may charge the power instead of storing the power.

  The power control unit 22 controls the energy harvesting element 21 and the secondary battery 23. The power supply control unit 22 controls power storage and discharge. The power supply control unit 22 sends the electric power generated by the energy harvesting element 21 to the information processing unit 20 or stores the electric power in the secondary battery 23. In addition, the power supply control unit 22 sends the electric power stored in the secondary battery 23 to the information processing unit 20.

  The RAM 25 of the power supply control unit 22 stores data used by the MCU 24. The RAM 25 according to the present embodiment stores information sent from the GW 3 and information acquired by the node 2. Specifically, the RAM 25 stores, as information transmitted from the GW 3, a standby time, a startup time, and the like designated by the GW 3. In addition, the RAM 25 stores, as information acquired by the node 2, an LQI (radio wave communication quality: Link Quality Indicator) indicating the received radio wave intensity of the received data, and a charged amount as a remaining battery level. The RAM 25 stores the LQI of the received data for each ID that identifies the node 2 that has transmitted the data.

  The ROM 26 stores a program used by the MCU 24. The ROM 26 has a parent node table and a child node table. The parent node table is an area for storing, as the parent node of the own node 2, an ID for identifying the parent node, for example, a MAC address. The child node table is an area for storing, as a child node of the own node 2, an ID for identifying the child node, for example, a MAC address.

  The sensor 27 is an element that detects a state of a sensing target. For example, the sensor 27 detects a landslide, a flood, and the like. The sensor 27 sends the detected information to the MCU 24. The wireless unit 28 is a part that performs wireless communication by multi-hop communication with another node 2 or the GW 3 existing within a predetermined wireless range. The wireless unit 28 performs wireless communication with, for example, a parent node upstream of the own node 2 and a child node downstream of the own node 2.

  The MCU 24 operates as a microcontroller, and drives the RAM 25, the ROM 26, the sensor 27, and the wireless unit 28. The MCU 24 reads a program stored in the ROM 26 and performs various processes based on the read program. The MCU 24 is activated when the remaining amount of the battery, which is the charged amount, becomes equal to or more than a predetermined amount. Further, the MCU 24 controls a start-up process, a standby process, and the like according to an instruction from the GW 3. Further, the MCU 24 measures the LQI, the remaining battery level, and the like, and transmits the measurement result from the wireless unit 28 to another node 2 or GW 3.

  Further, the MCU 24 transmits the information detected by the sensor 27 from the wireless unit 28 to the GW 3 which is the upstream side of the communication. As a result, the information detected by the sensor 27 is sent to the GW 3 via one or more nodes 2 or directly.

  The node 2 according to the present embodiment extends the standby time by waiting during a period other than the time period for performing the connection process. In other words, the node 2 according to the present embodiment is activated at the time of performing the connection processing, thereby shortening the activated time.

  FIG. 3 is a diagram illustrating an example of the control device 300. FIG. 3 illustrates a hardware configuration example of the control device 300 such as the GW3. The control device 300 such as a sensor control device has the same configuration as a general PC (Personal Computer) except that a wireless unit 35 that is a short-range wireless communication module is mounted. Specifically, the control device 300 includes a CPU (Central Processing Unit) 31, a RAM 32, a HDD (Hard Disk Drive) 33, a communication adapter 34, and a wireless unit 35. In the control device 300, the CPU 31, the RAM 32, the HDD 33, the communication adapter 34, and the wireless unit 35 are connected by a bus or the like. Electric power is supplied to the control device 300 from outside by wire. The control device 300 is realized by causing the CPU 31 to execute a prepared program.

  The HDD 33 is an example of a computer-readable recording medium. Various programs are stored in the HDD 33 in advance. The HDD 33 stores, for example, a connection processing program, a connection processing program, a determination program, a sleep instruction program, an acceptance processing program, and the like. Each program may be recorded in a memory (not shown), which is an example of a computer-readable recording medium, instead of the HDD 33. As the recording medium, for example, a portable recording medium such as a CD-ROM, a DVD disk, and a USB memory, and a semiconductor memory such as a flash memory may be used. The HDD 33 according to the present embodiment stores information sent from the node 2 and information acquired by the control device 300. Specifically, the HDD 33 stores unconnected node information 335A, connected node information 335B, and the like, which will be described later.

  The CPU 31 reads various programs stored in the HDD 33 and performs various processes based on the read various programs. The CPU 31 reads out each program from the HDD 33 and functions as a process on the RAM 32. The RAM 32 stores data used by the CPU 31.

  The communication adapter 34 is connected to the Internet 4 and acquires the environment information 5 of the place where the node 2 is located by using the Internet 4. The environment information 5 acquired by the communication adapter 34 is stored in the HDD 33 by the CPU 31. In addition, the communication adapter 34 transmits information collected by the node 2 (whether or not a landslide or a flood has occurred) to an external device such as a server using the Internet 4.

  The wireless unit 35 is a communication interface that collects information from the nodes 2 using multi-hop communication between the nodes 2.

  Next, a functional configuration example of the node 2 will be described. FIG. 4 is a block diagram illustrating a functional configuration example of the node 2. The node 2 includes an information processing unit 20, an energy harvesting element 21, a power control unit 22, and a secondary battery 23. Then, the information processing unit 20 includes a control unit 210, a communication unit 220, a storage unit 230, and the sensor 27. The communication unit 220 has the function of the wireless unit 28, the control unit 210 has the function of the MCU 24, and the storage unit 230 has the functions of the RAM 25 and the ROM 26.

  The communication unit 220 is a communication interface that communicates with the node 2 and the control device 300. The storage unit 230 has a parent node table 230A, a child node table 230B, and an LQI table 230C. The parent node table 230A is, for example, an area for storing an ID for identifying a parent node viewed from the own node 2 and a MAC address in association with each other. The child node table 230B is an area for storing, for example, an ID for identifying a child node viewed from the own node 2 and a MAC address in association with each other. The LQI table 230C is an area that stores the LQI of the received data for each ID that identifies the node 2 that has transmitted the data.

  The control unit 210 reads out a program stored in the storage unit 230 and executes various processes based on the read out program. The control unit 210 includes a calculation unit 210A, an addition unit 210B, and an instruction unit 210C.

  When receiving data from child node 2, calculation section 210A calculates LQI. For example, when the electric field strength (dBm) is P, the calculation unit 210A calculates LQI = (20P + 1970) / 7. The calculating unit 210A calculates the amount of stored power, which is the amount of power stored in the secondary battery 23. The adding unit 210 </ b> B adds the calculated LQI and the amount of stored power to the data transmitted to the control device 300.

  The instruction unit 210C generates instruction information and the like, and sends the generated instruction information to the communication unit 220. Thereby, the instruction unit 210C issues various instructions to the external device connected to the communication unit 220. For example, the instruction unit 210C instructs the communication unit 220 to transmit data to the control device 300. Further, when the node 2 is activated, the instruction unit 210C instructs the communication unit 220 to transmit a connection request to the parent node 2. When receiving the connection request from the child node 2, the instruction unit 210C instructs the communication unit 220 to transmit a response to the child node 2. When the connection process with the parent node 2 succeeds, the instruction unit 210C instructs the communication unit 220 to transmit a connection completion notification. Further, the instruction unit 210C instructs the components in the node 2 to change to the power outage power mode, change to the normal operation mode, stop the wireless module, start the wireless module, and the like.

  Next, an example of a functional configuration of the control device 300 such as the GW 3 will be described. FIG. 5 is a block diagram illustrating a functional configuration example of the control device 300. The control device 300 includes a control unit 310, a communication unit 320, and a storage unit 330. The communication unit 320 has functions of the wireless unit 35 and the communication adapter 34. The control unit 310 has a function of the CPU 31. The storage unit 330 has the functions of the RAM 32 and the HDD 33.

  The communication unit 320 is a communication interface that communicates with the node 2 and an external device. The storage unit 330 includes an unconnected node information storage unit 330A, a connected node information storage unit 330B, a node state storage unit 330C, and an environment information storage unit 330D. The unconnected node information storage unit 330A is an area for storing the unconnected node information generated by the control unit 310. The connection node information storage unit 330B is an area that stores the connection node information generated by the control unit 310. The node state storage unit 330C is an area for storing a connection state, an operation state, and the like of the node 2. The environment information storage unit 330D stores the environment information 5 acquired by the communication unit 320 using the Internet 4. The environment information 5 includes environmental performance information on the environment up to now and environmental prediction information on the environment in the future. The environmental performance information and the environmental prediction information are, for example, the amount of sunshine, temperature, humidity, or wind speed.

  The control unit 310 reads a program stored in the storage unit 330, and performs various processes based on the read program. Control unit 310 includes a connection processing unit 310A, a determination unit 310B, a sleep instruction unit 310C, and an acceptance processing unit 310D. The connection processing unit 310A controls a connection process with the node 2. The deciding unit 310B updates the information on the node 2 in the storage unit 330, and decides the reception date and time when the connection from another node 2 is received. For example, the determination unit 310B extracts the LQI and the remaining battery level from the data received from the node 2 through the communication unit 320, and updates the LQI and the remaining battery level stored in the storage unit 330. The sleep instructing unit 310C instructs the node 2 to put the node 2 into the sleep state until the reception date and time. The sleep instructing unit 310C according to the present embodiment sleeps on the node 2 selected as the path until the expected start date and time when it is expected that all nodes 2 on the path have accumulated enough power for connection or relay. Let it. After the node 2 attempts to accept the connection, the sleep instruction unit 310C causes each node 2 to sleep again. The acceptance processing unit 310D sets the node 2 to be accepted for connection based on the timing at which the unconnected node 2 starts.

  The node 2 may execute various processes using a microcomputer such as a CPU or an MPU (Micro Processing Unit) instead of or together with the MCU 24. The control device 300 may execute various processes using a microcomputer such as an MCU or an MPU instead of or together with the CPU 31.

  By the way, for example, in the case of energy harvesting using solar cells, electricity generation stops due to snow on the solar panel in winter, but at the same time, the surroundings of the node 2 are also covered with snow. In some cases, it is not necessary to do so. For example, in winter, measurements such as landslides due to floods may not be required.

  When the snow melts in spring, the power supply from the solar panel starts, but the secondary battery 23 is almost empty due to spontaneous discharge, leak current of the power supply circuit, etc., although measurement is not performed during winter. It is assumed that

  Therefore, the node 2 is activated when a certain amount of power is charged by the solar cell, and attempts to reconnect to the surrounding node 2. For example, in the daytime on a sunny day, the node 2 can perform the connection attempt, but the battery runs out at night, and the node 2 runs out at night or in a bad weather day. It is assumed that a connection attempt cannot be made.

  If the connection trial is started after the secondary battery 23 is sufficiently charged, the connection trial can be performed for a long period of time. However, when the capacity of the secondary battery 23 is larger than the amount of power generated by the solar battery, it takes a very long time to charge. . Further, in the control system 1, the connection is sequentially performed from the node 2 which is closer to the control device 300. For this reason, depending on conditions such as sunshine, when the network has extended to the vicinity of the terminal node 2, the terminal node 2 has exhausted the battery due to the connection attempt, and may wait for a long time until charging is completed again. There is also.

  On the other hand, power consumption can be suppressed by setting the node 2 to a sleep state in which no communication operation is performed, but during sleep, connection attempts from the neighboring nodes 2 cannot be accepted. Also, the node 2 in the sleep state does not perform the relay operation of the multi-hop communication. For this reason, the control device 300 of the present embodiment determines the sleep period of the node 2 in consideration of these factors.

  Specifically, the control device 300 acquires the environment information 5 such as the weather forecast from the Internet 4 and predicts the date and time at which the unconnected node 2 will make a connection attempt based on the weather forecast. Then, the control device 300 controls the sleep of the node 2 so that another connected node 2 wakes up at the predicted date and time. Thus, it can be expected that the unconnected node 2 can be collected while charging the secondary battery 23. Note that the node 2 starts a connection attempt when the power is recovered even a little, and causes the control device 300 to sleep immediately after connection, thereby allowing the control device 300 to control the battery while charging.

  Thereby, even when the node 2 is not sufficiently charged and cannot operate for a long time, the connection setting between the nodes 2 can be efficiently performed. In addition, since the node 2 enters the sleep state at an appropriate timing not only for the sensing operation but also for the communication relay operation, it is possible to efficiently use power even when a plurality of nodes 2 occur simultaneously. Becomes

  Next, an operation flow of the node 2 and the control device 300 will be described. First, an operation flow when the node 2 starts up and an operation flow when the node 2 waits for reception will be described. Thereafter, as the operation flow of the control device 300, an operation flow of a standby state, an operation flow of an update process, an operation flow of a sleep process, and an operation flow of a post-acceptance process will be described.

  In the following description, the node 2 that starts and issues a connection request to the parent node or the control device 300 may be referred to as a node 2X or a child node 2X. The parent node that receives the connection request from the node 2X may be referred to as the node 2Y or the parent node 2Y. Therefore, in this embodiment, the node 2X is an unconnected child node, and this node 2X tries to connect to the parent node 2Y. In this embodiment, the node 2Y is a connected parent node, and the node 2Y attempts to accept a connection request from the child node 2X. A child node that transmits a connection request to the node 2X may be referred to as a node 2Z or a child node 2Z.

  FIG. 6 is a flowchart illustrating an example of a processing operation when the node 2 is activated. In the node 2X which is a wireless sensor node, when the energy harvesting element 21 starts power generation from a state where the secondary battery 23 is empty or almost empty, the power supply control unit 22 of the node 2X starts charging the secondary battery 23. Specifically, the energy harvesting element 21 of the node 2X starts supplying power to the secondary battery 23 using sunlight or the like (step S11).

  When the charging of the secondary battery 23 at the node 2X progresses and the terminal voltage of the secondary battery 23 exceeds the operating voltage of the MCU 24 to some extent, the power supply control unit 22 of the node 2X starts supplying power to the control unit 210 which is the MCU 24. I do. Upon receiving the power supply, the instruction unit 210C of the node 2X activates the communication unit 220, which is a wireless module (step S12), and causes the communication unit 220 to transmit a request for connection to a network. As a result, the node 2X transmits a request for connection to the network to the nearby node 2Y (step S13). The node 2Y to which the connection request to the network is transmitted is the node 2 arranged higher in the tree structure than the node 2X.

  After the connection request is transmitted, the instruction unit 210C of the node 2X determines whether or not there is a response from the node 2Y (Step S14). If there is no response (No at Step S14), the node 2X waits for a certain time (Step S15), and thereafter transmits a connection request to the nearby node 2Y to the network (Step S13). As described above, when there is no response from the node 2Y, the connection request is retransmitted after waiting for a certain period of time.

  The node 2X repeatedly waits for a certain period of time, transmits a connection request, and determines whether there is a response until a response is received. The node 2X performs at least transmission of the connection request and determination of the presence or absence of a response as one cycle of the connection request. When the power used in one cycle of the connection request exceeds the power generation amount of the energy harvesting, the power storage amount of the secondary battery 23 gradually decreases. Then, when the terminal voltage of the secondary battery 23 falls below the operating voltage of the MCU 24, the power supply control unit 22 stops supplying power to the MCU 24, thereby stopping the operation of the MCU 24. Thereafter, when the capacity of the secondary battery 23 is restored by charging again, the MCU 24 is restarted by feeding power, whereby the processes of steps S11 to S15 are repeated.

  If there is a network-connected node 2Y near the node 2X so as to accept the connection with the node 2X, the node 2Y returns a response to the connection request to the node 2X. Therefore, when there is a response from the node 2Y to the node 2X (Yes at Step S14), the instruction unit 210C of the node 2X causes the communication unit 220 to execute a connection process with the node 2Y (Step S16). As a result, a network connection process is performed between the nodes 2X and 2Y, and as a result, a network connection is established. The state in which the connection is accepted means, for example, a state in which the wireless module of the node 2Y is in a receiving state, and as a result, can receive a connection request from the node 2X.

  After the network connection processing between the nodes 2X and 2Y is established, the instruction unit 210C of the node 2X causes the communication unit 220 to transmit a notification of connection to the GW 3 that is the control device 300 (Step S17). The connection notification is a notification indicating that the network connection processing between the nodes 2X and 2Y has been established. Thereafter, the node 2X transitions to a reception standby state.

  FIG. 7 is a flowchart illustrating an example of a processing operation of the node 2 in a reception standby state. When receiving the sleep instruction from the control device 300, the node 2Y in the reception standby state waits in the sleep state for the time specified by the sleep instruction. Specifically, the instruction unit 210C of the node 2Y stops the communication unit 220, which is a wireless module (Step S21).

  Then, the instructing unit 210C of the node 2Y changes the operation mode of the control unit 210, which is the MCU 24, to the power outage power mode in which the power is smaller than the normal operation mode (step S22). The power outage mode is an operation mode in which the MCU 24 enters a sleep state. In the sleep state, the communication unit 220 does not perform wireless transmission / reception processing, and the MCU 24 also stands by in the low power consumption state. Therefore, the power consumption can be greatly reduced, and the secondary battery 23 can be focused on correspondingly. On the other hand, in the sleep state, the communication unit 220 of the node 2Y does not perform wireless transmission / reception, and therefore cannot respond even if the nearby node 2X transmits a connection request.

  After the transition of the node 2Y to the power outage mode, the instruction unit 210C of the node 2Y waits until the designated time designated by the sleep instruction (Step S23). When the waiting for the specified time is completed, the instruction unit 210C of the node 2Y changes the operation mode of the control unit 210, which is the MCU 24, to the normal operation mode in which the operation is performed at a higher power than the power outage power mode (step S24). Further, the instruction unit 210C of the node 2Y activates the communication unit 220, which is a wireless module (step S25), and then enters a reception standby state.

  When the node 2Y in the reception standby state receives a connection request from the node 2X, which is a child node, the instruction unit 210C of the node 2Y causes the communication unit 220 to transmit a connection response to the node 2X (step S26). Thereby, a network connection process between the nodes 2X and 2Y is established. Thereafter, the node 2Y enters a reception standby state.

  Note that also when the node 2X receives a connection request from the node 2Z which is a child node, the instruction unit 210C of the node 2X causes the communication unit 220 to transmit a connection response to the node 2Z. As a result, a network connection process between the nodes 2X and 2Z is established. Thereafter, the node 2X enters a reception standby state.

  When the node 2Y in the reception standby state receives the state measurement instruction from the control device 300, the node 2Y measures the data specified by the state measurement instruction (step S27). The state measurement instruction from control device 300 includes an instruction to measure LQI of node 2Y and an instruction to measure the remaining battery level of node 2Y. The calculation unit 210A of the node 2Y calculates the LQI for each nearby node 2 as the state measurement. The calculation unit 210A of the node 2Y calculates the remaining battery level of the node 2Y as the state measurement. The communication unit 220 transmits the calculated LQI and the remaining battery level to the control device 300 according to the instruction from the instruction unit 210C. The communication unit 220 of the node 2Y transmits the LQI and the remaining battery level to the parent node 2Y or the control device 300. Accordingly, the LQI and the remaining battery level are transmitted to the control device 300 directly or via one or more nodes 2 (step S28). Thereafter, the node 2Y enters a reception standby state.

  FIG. 8 is a flowchart illustrating an example of a processing operation of the control device 300 in a standby state. In the control device 300 in the standby state, when the communication unit 320 receives a connection request from the child node 2, the connection processing unit 310A transmits a connection response to the node 2 (Step S31). Then, control device 300 enters a standby state.

  Further, since the control device 300 in the standby state is supplied with the external power, the control device 300 can always be in a reception state, that is, a state in which a connection request can be accepted. For this reason, the node 2 in the vicinity of the control device 300, that is, in a place where direct communication is possible, can be connected to the control device 300 immediately after startup.

  In the control device 300 in the standby state, when the communication unit 320 receives the connection notification indicating the completion of the connection between the nodes 2X and 2Y from the node 2X, the connection processing unit 310A connects the child node 2X which is the transmission source node. The state is recorded as a node (step S32). In this case, when a new node 2 is connected, the control device 300 collects and records the current battery remaining amount and the like of the connected node 2. Specifically, the connection processing unit 310A registers the entry of the child node 2X, the remaining battery level of the child node 2X, and the like in the connected node information 335B in the connection node information storage unit 330B. Further, the connection processing unit 310A deletes the entry of the child node 2X from the unconnected node information 335A in the unconnected node information storage unit 330A. Further, control device 300 transmits a sleep instruction until the next update date and time to child node 2X that is the transmission source node (step S33). Then, control device 300 enters a standby state. Note that, even when the node 2Z is a child node, the node 2Z performs the same processing as the node 2X.

  Further, in the control device 300 in the standby state, the determination unit 310B starts preparations for updating the unconnected node information 335A and the connected node information 335B immediately before the update date and time for updating the setting of the sleep state, etc. When the preparation is completed, an update process is performed. The deciding unit 310B may set the update date and time at which the update process is executed periodically at an arbitrary time interval, for example, 12 hours or 24 hours, or may take the characteristics of energy harvesting into the morning and noon. It may be set at any timing.

FIG. 9 is a diagram illustrating a configuration example of the unconnected node information 335A. The unconnected node information 335A includes a node ID for identifying the node 2, an LQI, a correlation coefficient (α _n ), an estimated last stop date and time (t ' _ne ), an estimated start date and time (t _n ), This is information in which a connection acceptance time is associated with.

  The LQI is the communication quality with another node 2 and is registered in the unconnected node information 335A for each other node 2. The correlation coefficient is a coefficient for predicting the power generation amount of the unconnected node 2X, and is a coefficient corresponding to the correlation between the environmental information 5 and the power generation amount. The correlation coefficient corresponds to the power characteristic of the node 2X. The estimated last stop date and time is the date and time at which the node 2X is estimated to have stopped last time.

  The node 2 </ b> X stops operating after the time corresponding to the amount of stored power and the operating power has elapsed, since the amount of stored power decreases as the node 2X operates. Therefore, the determination unit 310B calculates the estimated last stop date and time based on the amount of stored power, the power in operation, and the like. The estimated activation date and time is the date and time when the node 2 is estimated to be activated. In the unconnected node information 335A, the estimated start date and time of the unconnected node 2X is registered. The node 2 restarts when the capacity of the secondary battery 23 recovers by charging. Therefore, the determination unit 310B calculates the estimated activation date and time based on the transition of the charged amount and the like. The connection acceptance time is a processing time in which the node 2 accepts a connection from another activated node 2. In other words, the connection acceptance time is a period set for the node 2 and a period for accepting a connection from another node 2. Therefore, the determination unit 310B calculates the connection acceptance time based on the processing time for one cycle when performing a connection attempt and the number of cycles.

FIG. 10 is a diagram illustrating a configuration example of the connected node information 335B. The connected node information 335B includes a node ID for identifying the GW 3 or the node 2 that is the control device 300, the LQI, the remaining battery level (P _n ) [mWh], the correlation coefficient (α _n ), This is information in which the activation date and time (t _n ) is associated with the neighbor exclusion node. The LQI and correlation coefficient of the connected node 2Y are registered in the connected node information 335B. Note that the control device 300 is supplied with power from the outside by wire, so that the battery remaining amount and the correlation coefficient are not registered. In addition, as for the control device 300, there is no parent node 2 so that no neighbor exclusion node is registered.

  The battery remaining amount is the remaining amount of power stored in the secondary battery 23 of the node 2Y. The remaining battery level is obtained from the node 2Y and registered in the connected node information 335B. The halfway start date and time is the date and time when the control device 300 or the node 2Y starts in the middle of the sleep state. In other words, the midway activation date and time is an acceptance date and time at which the control device 300 or the node 2Y accepts a connection from the child node 2X. The determination unit 310B calculates the midway activation date and time based on the LQI, the remaining battery level, and the like. The neighbor exclusion node is a node 2 that is excluded as a child node 2X among unconnected nodes 2X arranged near the node 2Y. The determination unit 310B registers the node 2X, which is a connection acceptance target, as a neighboring exclusion node when the connection between the node 2X, which is a connection acceptance target, and the control device 300 fails.

  The determining unit 310B collects the unconnected node information 335A based on the LQI before stopping the node 2 and records it in the storage unit 330. After the connection with the node 2, the determining unit 310B determines the connected node 2 as the unconnected node. It is deleted from the information 335A. Then, the determining unit 310B creates connected node information 335B from information collected after the connection.

  FIG. 11 is a flowchart illustrating an example of the update processing operation of the control device 300. The control device 300 acquires the environment information 5 immediately before the update date and time (step S41). Specifically, the control device 300 obtains the environmental performance information of the node 2 and the environment prediction information of the node 2 from the Internet 4 a predetermined time before the update date and time. The environmental information 5 is, for example, the amount of sunlight when the solar power generation uses solar cells, and the wind speed when the wind power is used. After acquiring the environment information 5, the control device 300 waits until the update date and time (step S42).

  When the update date and time comes, all the connected nodes 2 are released from the sleep state, so that the control device 300 can communicate with all the connected nodes 2. As a result, the determination unit 310B of the control device 300 communicates with the connected node 2 and causes the node 2 to measure the current power storage amount and the communication quality between the control device 300 and the nearby node 2. . Then, the determination unit 310B collects the measurement results from the node 2, and records the measurement results in the storage unit 330. Specifically, the determination unit 310B transmits an LQI acquisition request to all connected nodes 2 (Step S43). Then, the determining unit 310B registers the LQI acquired from the node 2 in the connected node information 335B, and updates the LQI (step S44). The determining unit 310B transmits a battery remaining amount acquisition request to all connected nodes 2 (step S45). Then, the determining unit 310B registers the remaining battery amount acquired from the node 2 in the connected node information 335B. Either the processing of step S43 or the processing of step S45 may be performed first or may be performed simultaneously.

When the collection of the battery remaining amount as the storage amount and the LQI as the communication quality is completed, the determination unit 310B calculates a correlation coefficient between the environment information 5 and the power generation amount for predicting the power generation amount of the connected node 2. Is calculated, and the correlation coefficient in the connected node information 335B is updated (step S46). When updating the correlation coefficient, the determination unit 310B acquires the current power storage amount (P _n1 ) and the power storage amount (P _n2 ) at the previous measurement from the node 2. Determining unit 310B updates the current of the charged amount (P _n1) a is the node 2 of the battery remaining amount (P _n) in the connected node information 335B (step S47).

  The environmental information 5 such as the amount of sunshine and the wind speed available from the Internet 4 is uniform over a wide range, but since the sunshine and the windfall vary depending on the installation conditions of the node 2, the determining unit 310B determines the correlation coefficient by Set individually.

The determination unit 310B calculates the correlation coefficient (α _n ) at the n-th (n is a natural number) node 2 using, for example, the following equation (1). That is, the determination unit 310B determines the ideal power generation amount (E _I ), the current power storage amount (P _n1 ), the power storage amount at the previous measurement (P _n2 ), and the power consumption per unit time (W _s ) And the elapsed time (t) from the previous measurement are used to calculate a correlation coefficient (α _n ). The ideal power generation amount (E _I ) in the equation (1) is calculated based on the environment information 5 and the design information of the energy harvesting element 21.

The determination unit 310B calculates a correlation coefficient (α _n ) for all connected nodes 2 and records the calculated correlation coefficient in the connected node information 335B. Here, the configuration of the environment information 5 will be described. FIG. 12 is a diagram illustrating a configuration example of the environment information 5330D. Here, a description will be given of a case where the environment information 5330D has a configuration including environmental performance information and environmental prediction information. The environment information 5330D is information in which a region, a date, a time, a measured value of sunlight, and a predicted value of sunlight are associated with each other.

  The area is a place where the node 2 is arranged, and is a target area for which the environment information 5330D is set. The date is the date when the amount of sunlight in the environment information 5330D was obtained, and the time is the time when the amount of sunlight in the environment information 5330D was obtained. Further, the actual measurement value of the sunshine amount is the actual result of the sunshine amount actually measured in the area in the environment information 5330D. The predicted value of the amount of sunshine is the amount of sunshine predicted in the future in the area of the environmental information 5330D. The actual measurement value of the amount of sunlight is measured using an actual measurement device or the like, and the determination unit 310B acquires the actual measurement value using the Internet 4. The predicted value of the amount of sunshine is derived from a weather forecast or the like, and the determination unit 310B acquires the predicted value using the Internet 4. The environmental performance information is information in which the area, the date, the time, and the measured value of the amount of sunshine are associated with each other in the environmental information 5330D. The environment prediction information is information in which a region, a date, a time, and a predicted value of sunlight are associated with each other in the environment information 5330D.

For example, it is assumed that a record of the amount of sunlight (L _i ) of the target area every hour is distributed via the Internet 4 as the environmental information 5330D. In this case, the determining unit 310B determines the power generation amount (W (L _i )) Can be obtained. Therefore, the determination unit 310B can obtain the ideal power generation amount (E _I ) by integrating the power generation amount per unit time from the previous measurement date and time to the current date and time. Specifically, the determination unit 310B calculates an ideal power generation amount (E _I ) using the following equation (2).

  When the information update of the connected node 2 is completed, the determination unit 310B extracts the unconnected node 2 near the connected node 2. In other words, when the update of the connected node information 335B and the environment information 5330D is completed, the determination unit 310B extracts the node 2 near the connected node 2 from the unconnected nodes 2 (step S48). In this case, in order to extract the node 2, the determining unit 310B acquires the communication quality between the nodes 2 and records the acquired communication quality in the connected node information 335B before the energy harvesting cannot be performed and the node 2 stops. deep. For example, the determining unit 310B acquires the communication quality from each node 2 before snow starts. Based on the connected node information 335B, the determination unit 310B extracts an unconnected node 2 whose communication quality with the connected node 2 is equal to or more than a threshold for both transmission and reception as a non-connected neighboring node 2. .

  Next, the determination unit 310B estimates the date and time when each of the extracted unconnected neighboring nodes 2 is activated by energy harvesting and performs a connection trial operation. In other words, the determination unit 310B calculates the estimated start date and time of the extracted node 2 (step S49). Although the correlation coefficient of each node 2 is used for this calculation, the determination unit 310B uses the above-described method using the equation (1) or the like before the node 2 is stopped for the unconnected node 2. Then, the correlation coefficient of the unconnected node 2 is calculated and recorded. Then, the determining unit 310B uses the recorded correlation coefficient of the unconnected node 2. The determining unit 310B predicts the amount of power stored in the node 2 in each time interval from the correlation coefficient, the actual environmental information, and the environmental prediction information. Then, the determining unit 310B predicts that the date and time when the predicted amount of power storage exceeds the amount of power required for the operation of the node 2 is the date and time when the node 2 can start up and start a connection attempt. The date and time when the connection attempt is predicted to be started is a predicted start date and time at which the node 2 can start up and start the connection attempt.

  When the connection attempt is started, the power consumption of the node 2 is greatly increased, and the remaining battery power is gradually reduced. When the amount of stored power is exhausted, the node 2 stops operating and terminates the connection attempt. If the period from the expected start date and time of the connection attempt to the expected end date and time of the connection attempt is longer than the period required for the node 2 to accept the connection, the determination unit 310B estimates that the node 2 will perform the connection attempt.

The power generation amount per unit time of each node 2 is a value obtained by multiplying the ideal power generation amount W (L _i ) obtained from the environment information 5 and the design information of the energy harvesting element 21 by the correlation coefficient α. At the end of the previous connection attempt, the remaining amount of the secondary battery 23 should be exhausted. Therefore, if the date and time when the previous connection attempt is predicted to be ended is assumed to be t ' _ne , the power storage of the node n at the time and date t is assumed. The amount _Pn can be calculated using the following equation (3), where _Wl is the power consumption, which is the amount of discharge due to leakage or the like. Therefore, the determination unit 310B calculates the charged amount _Pn using the following equation (3).

The date and time when the charged amount (P _n ) of the equation (3) exceeds the operable threshold value (P _t ) is the expected connection start date and time t _ns . On the other hand, during the connection attempt to increase power consumption W _c, quantity of stored power in the time t (t> t _ns) can be calculated using the following equation (4). Therefore, the determination unit 310B calculates the charged amount _Pn using the following equation (4).

The date and time when P _{n in} equation (4) becomes 0 is the connection attempt end date and time t _ne . The deciding unit 310B predicts that the unconnected node 2 will perform the connection attempt, and sets the date and time when the connection acceptance is predicted to start and the connection acceptance start date and time when the connection acceptance is performed just in the middle between the end and the prediction date and time. Assume the estimated start date and time. The period required for accepting a connection is, for example, about several cycles of a cycle for performing a connection attempt. When the period for the connection attempt to the node n and p _n, estimated start time (t _n) can be calculated from the following equation (5). Therefore, the determination unit 310B calculates the estimated activation date and time (t _n ) using the following equation (5).

The deciding unit 310B selects the earliest unselected estimated activation date and time (ti: node i) (step S50). In other words, determination section 310B selects the earliest time ti of the estimated start time t _n of the nodes of the plurality of unconnected 2. Here, the earliest date and time of the estimated starting time t _n is explained for the case where the date and time t _1.

Determination unit 310B, the time ti can be selected, and the date and time t ₁ is determined whether the next update date and time previously (step S51). When the date and time ti cannot be selected (No at Step S51), the control device 300 shifts to a sleep process for the node 2. In addition, if it is later than the date and time t ₁ is the next update date and time (step S51: No), the determining section 310B determines that this time does not perform the acceptance. Then, a transition is made to sleep processing for the node 2.

On the other hand, if it is before time t ₁ than the next update date and time (step S51: Yes), the determining unit 310B determines the connection acceptance by the node 2 by corresponding to time t ₁ selected. Then, the determining unit 310B estimates the power storage amount P _n ′ of the connected node 2 at the date and time ti (t1) (Step S52). The power storage amount P _n ′ is, as described above, the current power storage amount P _n measured at each node 2, the correlation coefficient α _n calculated from the power storage amount P _n , and the sunshine amount (L _i ) and it can be calculated by using the power consumption W _s sleeping. Therefore, the determination unit 310B calculates the charged amount P _n ′ using the following equation (6). Note that the current storage amount _Pn is calculated using the above equation (3) or equation (4).

Further, when calculating the power storage amount P _n ′ of each node 2, the determining unit 310B determines the node 2 that performs relay between the node i that has determined to accept the connection and the control device 300. At this time, the determination unit 310 </ b> B determines one or more nodes 2 corresponding to the path from the node i that has been determined to receive the connection to the control device 300. As a result, the determination unit 310B searches for the entire route from the node i that has determined to receive the connection to the control device 300. As described above, the determining unit 310B selects a route to the node i that has been determined to receive the connection (step S53).

  There are various route search methods, and an example will be described here. The determination unit 310B traces, with a single stroke, the node 2 that has been connected in the vicinity of the unselected node i that has been determined to receive the connection and for which both communication qualities exceed the threshold, and extracts all routes that reach the control device 300. I do. Then, the determining unit 310B determines whether a route to the node i is selectable (Step S54).

  When determining that the route to the node i is not selectable (No at Step S54), the determining unit 310B repeats the processes of Steps S50 to S54 until it is determined that the route to the node i is not selectable.

  The determination unit 310B determines that the route is acceptable if the power storage amounts of all the nodes 2 on the route exceed the power required for connection acceptance (step S54: Yes). The determining unit 310B selects a route to the node i that has been determined to receive the connection from the acceptable routes.

During acceptance of connection to become node 2 also all be node 2 for relaying reception standby state in the receiving, multiplied by acceptance period p _n to the power consumption W _R in a reception standby state is power consumption. The power consumption in the reception standby state only needs to be smaller than the expected power storage amount.

  When the number of connected nodes is large, there is a possibility that a plurality of routes may be acceptable. In this case, the determination unit 310B preferentially selects, for example, a route with a small number of relays to the control device 300. If the number of relays is the same, the determination unit 310B compares the nodes 2 with the smallest expected power storage amount in the route and selects the route with the larger expected power storage amount. The deciding unit 310B selects one route by weighting with the number of relays of the node 2, the estimated power storage amount, the correlation coefficient, or the like.

  FIG. 13 is a diagram for explaining an example of the route selection method. For example, there are five nodes 2 from “K” to “O” in the control system 1, and nodes “K”, “L”, and “M” are currently connected, and “N”, “O” Is unconnected. In this case, assuming that the arrows in FIG. 12 indicate the neighborhood relationship between the respective nodes, for node 2 of “O”, “O” → “L” → controller 300, “O” → “L” There is a path of “→ K” → controller 300, “O” → “M” → “L”, “O” → “M” → “L” → “K” → controller 300.

  For example, if the expected storage amounts of the nodes 2 of “K” and “L” exceed the required amount of energy but do not exceed the node 2 of “M”, the acceptable path is “O” → “ L ”→ control device 300,“ O ”→“ L ”→“ K ”→ control device 300. The deciding unit 310B selects a route of “O” → “L” → control device 300 having the smallest number of hops from the two routes.

Determination unit 310B, once the route can be selected to record that starts with the time t ₁ to the node 2 on the path. Specifically, determining unit 310B are nodes 2 and the control device 300 on the route GW3 can be added the date and time t ₁ during start date and time are stored (step S55). Then, the determining unit 310B repeats the processing of steps S50 to S55 until there is no more selectable route. For example, determination unit 310B After storing the midway start date and time node 2 date t _1, with respect to earlier estimated start time t ₂ of the node 2 to the next time t ₁ of time t ₁ node 2 the same Perform processing. However, with respect to node 2 selected as the route date t _1, in order to consume the power of W _R × p _n by waiting, determining unit 310B, when predicting the charged amount, the power fraction for the consumption Calculate by subtracting. Thereafter, the determining unit 310B performs the same processing for all unconnected nodes 2 whose estimated activation date and time are earlier than the next update date and time. As a result, the halfway start date and time to be started by the next update date and time are recorded in the node 2 and the connected node information 335B, and the sleep instructing unit 310C of the control device 300 determines the halfway start date and time in the connected node information 335B. , A sleep instruction is issued to the node 2.

  FIG. 14 is a flowchart illustrating an example of the sleep processing operation of the control device 300. If the sleep instructing unit 310C of the control device 300 records the halfway start date and time for each node 2, the sleep instructing unit 310C records the halfway start date and time so that the node 2 starts up at the earliest date and time. A sleep instruction is transmitted to the node 2. The sleep instruction unit 310C transmits a sleep instruction to the node 2 that has not recorded the halfway activation date and time so as to sleep until the next update date and time.

  Hereinafter, a specific instruction procedure of the sleep processing will be described. The sleep instructing unit 310C sequentially selects the unselected connected nodes 2. Here, the sleep instruction unit 310C selects one unconnected connected node 2 (step S61). Then, the sleep instruction unit 310C checks whether the node 2 can be selected (Step S62). If the selection is possible (Yes at Step S62), the sleep instructing unit 310C acquires the shortest halfway activation date and time of the selected node 2 from the connected node information 335B (Step S63). Then, the sleep instructing unit 310C checks whether the shortest halfway activation date and time can be acquired (step S64). When it is possible to acquire (Step S64 affirmative), the sleep instructing unit 310C transmits a sleep instruction instructing to sleep until the acquired halfway activation date and time to the selected node 2 (Step S65). On the other hand, if the midway activation date and time cannot be acquired (No at Step S64), the sleep instruction unit 310C transmits a sleep instruction to instruct to sleep until the next update date and time to the selected node 2 (Step S66). ). After transmitting the sleep instruction up to the halfway activation date and time or the sleep instruction until the next update date and time to the node 2, the sleep instruction unit 310C repeats the processing of steps S61 to S66.

  If it is not possible to select the node 2 in the processing of step S62 (No at step S62), the reception processing unit 310D acquires the shortest halfway activation date and time of the GW 3 that is the control device 300 from the connected node information 335B. (Step S67). In other words, when the sleep instruction is completed to all the nodes 2, the reception processing unit 310 </ b> D acquires the midway activation date and time of the control device 300. The midway activation date and time of the control device 300 is a date and time for the control device 300 to issue a sleep instruction again to the node 2 that has executed the connection acceptance process. The reception processing unit 310D confirms whether it was possible to acquire the halfway activation date and time when attempting to acquire the halfway activation date and time (step S68). If it is not possible to acquire the midway activation date and time (No at Step S68), the reception processing unit 310D causes the control device 300 to be in a standby state. On the other hand, if the acquisition is possible (Yes at Step S68), the reception processing unit 310D sets the unconnected node 2 with the acquired halfway activation date and time as the estimated activation date and time as the reception target (Step S69).

  Further, the reception processing unit 310D acquires the connection reception time of the node 2 to be received (step S70). Then, the reception processing unit 310D causes the control device 300 to be in a standby state during the midway activation date / time + connection reception time (step S71). Thereafter, control device 300 performs post-acceptance processing.

  Each node 2 sleeps for a time instructed by the control device 300, and then starts up and enters a reception standby state. At this time, if a connection request comes to any of the nodes 2, the node 2 accepts the connection in response to the connection request. Then, the connected node 2 transmits a connection notification to the control device 300 via another activated node 2. In the control device 300, when the node 2 enters the connection acceptance state, the acceptance processing unit 310D executes post-acceptance processing.

  FIG. 15 is a flowchart illustrating an example of a post-accepting processing operation of the control device 300. In addition, among the processing illustrated in FIG. 15, the description of the same processing as the processing illustrated in FIG. 14 may be omitted.

  The sleep instructing unit 310C sequentially selects the unselected connected nodes 2. Here, the sleep instructing unit 310C selects one unselected connected node 2 (step S81). Then, the sleep instruction unit 310C checks whether the node 2 can be selected (Step S82). If the selection is possible (Yes at Step S82), the sleep instructing unit 310C compares the midway activation date and time of the selected node 2 with the estimated activation date and time of the accepting node 2 based on the connected node information 335B. (Step S83). Then, sleep instructing section 310C determines whether or not there is a match between the selected start-up date and time of node 2 and the estimated start-up date of node 2 to be accepted. In other words, the sleep instruction unit 310C determines whether the selected node 2 is currently operating (Step S84).

If there is no match between the selected start date and time of the node 2 and the estimated start date and time of the node 2 to be accepted (No at Step S84), the sleep instructing unit 310C determines that the selected node 2 Judge that it is not operating. Since sleep instruction unit 310C does not need to issue a sleep instruction to node 2 that is not operating, sleep instruction unit 310C returns to the process of step S81. On the other hand, if there is a match between the midway activation date and time of the selected node 2 and the estimated activation date and time of the target node 2 (Yes at step S84), the sleep instructing unit 310C returns The early start date and time is acquired from the connected node information 335B (step S85). Then, the sleep instructing unit 310C checks whether it is possible to acquire the next earlier start date and time after the present (step S86). When the sleep instruction can be acquired (Yes at Step S86), the sleep instruction unit 310C transmits the acquired sleep instruction up to the halfway activation date and time to the selected node 2 (Step S87). Thus, the node sleep instruction unit 310C, after waiting time p ₁ is the response completion time between the time t ₁ + child node 2 to the earliest start among all the nodes 2, which is activated at that time 2, a sleep instruction until the next halfway activation date and time is transmitted.

  On the other hand, when it is not possible to acquire the halfway activation date and time (No at Step S86), the sleep instruction unit 310C transmits a sleep instruction until the next update date and time to the selected node 2 (Step S88). After transmitting the sleep instruction up to the halfway activation date and time or the sleep instruction until the next update date and time to the node 2, the reception processing unit 310D repeats the processing of steps S81 to S88.

  If it is not possible to select the node 2 in the processing of step S82 (No at step S82), the reception processing unit 310D sets the node 2 set as the connection target (hereinafter, may be referred to as the target node 2). ) Is determined (step S89). Thereby, the reception processing unit 310D checks whether the expected node 2 has been connected.

  If the connection has not been made (No at Step S89), the reception processing unit 310D estimates that the communication state and the power generation environment have changed, and corrects the prediction. Specifically, the reception processing unit 310D searches for an operating connected node 2 near the reception target node 2 (step S90). Then, the reception processing unit 310D sets the connected node 2 that has been waiting from the reception target node 2 as a neighbor exclusion node, and records the same in the connected node information 335B (step S91). The neighbor exclusion node is located near the accepting node 2 and operates, and waits from the accepting node 2, but fails to successfully connect the accepting node 2 to the control device 300. 2. In this way, the reception processing unit 310D marks, for example, the node 2 that has waited for the connection of the reception target node 2 to be excluded from the nearby nodes 2 when correcting the prediction, and sets the other nearby nodes 2 2 to try to connect.

  The reception processing unit 310D searches for all connected nodes 2 that are operating near the reception target node 2 (step S92). Then, the acceptance processing unit 310D determines whether or not all of the searched connected nodes 2 are set as neighbor exclusion nodes for the acceptance target node 2. In other words, the reception processing unit 310D determines whether all the connected nodes 2 that have been searched are excluded from the nodes 2 near the reception target node 2 (step S93).

  In the case where the receiving target node 2 has excluded all the searched connected nodes 2 from the nodes 2 in the vicinity of the receiving target node 2 (Yes at Step S93), the receiving processing unit 310D determines that all of the searched connected nodes 2 have been detected. The node 2 is deleted from the neighbor exclusion nodes to increase the connection acceptance time of the acceptance target node 2 (step S94). In other words, the acceptance processing unit 310D sets the searched connected node 2 as a neighbor exclusion node, and as a result, when there is no longer a node 2 near the acceptance target node 2, it removes the exclusion mark and connects Increase the receiving time by one to several cycles. The reception processing unit 310D increases the connection reception time, performs a process of newly attempting to connect to the reception target node 2, and sets the neighboring node 2 that has waited for the connection when the connection was not established, as the neighboring exclusion node. When set, the process is repeated. Thus, the control device 300 can cope with a case where the power generation amount or the communication environment changes.

  If the control device 300 has been able to connect to the reception target node 2 (Yes at Step S89), the reception processing unit 310D acquires the next halfway activation date and time of the GW 3 that is the control device 300 (Step S95). In addition, if the result of step S93 is negative, or if the control device 300 can connect to the reception target node 2 after step S94, the reception processing unit 310D acquires the next halfway activation date and time of the GW 3 that is the control device 300 (step S94). S95).

  Then, the reception processing unit 310D checks whether the next halfway activation date and time can be acquired (step S96). If acquisition is not possible (No at Step S96), the reception processing unit 310D causes the control device 300 to enter a standby state. On the other hand, when the acquisition is possible (Yes at Step S96), the reception processing unit 310D sets the unconnected node 2 having the acquired midway activation date and time as the estimated activation date and time as the reception target (Step S97). Further, the reception processing unit 310D acquires the connection reception time of the node 2 to be received (step S98). Then, the reception processing unit 310D causes the control device 300 to be in a standby state during the midway activation date / time + connection reception time (step S99). Thereafter, control device 300 performs post-acceptance processing. As described above, the determining unit 310B determines the remaining battery level of the node 2Y, the LQI between the nodes 2X and 2Y, the correlation coefficient of the node 2X, and the environment information 5 at the position where the node 2X is located. Thus, the connection acceptance date and time at which the node 2Y accepts the connection with the node 2X is determined. Then, sleep instruction unit 310C instructs node 2Y to put node 2Y into the sleep state until the connection acceptance date and time.

  When the next update date and time arrives, the control device 300 is in a state where all the devices including the newly connected node 2 have been activated. For this reason, the control device 300 repeats the same processing as described above for the activated node 2, and increases the number of connected nodes 2 while recovering the secondary battery 23 by sleep.

  According to the above-described processing, the time or the number of nodes to be activated for accepting the connection of the unconnected node 2X can be suppressed, so that the power storage amount can be recovered by sleep while accepting the unconnected node 2X. .

  When receiving a sleep instruction from the control device 300 until the reception date and time, the node 2 enters a sleep state until the reception date and time. As a result, each node 2 can be in a sleep state until the reception date and time according to the sleep instruction from the control device 300.

  Since each node 2 can be in the sleep state until the reception date and time, the power storage amount can be increased. As a result, the control device 300 can efficiently perform the connection setting between the nodes 2.

  The determination unit 310B determines the node 2Y based on the remaining battery level of the connected node 2Y, the LQI between the nodes 2X and 2Y, the correlation coefficient that is the power characteristic of the node 2X, and the environment information 5 of the node 2X. Determines the connection acceptance time for accepting the connection of the node 2X. As a result, the control device 300 can cause the node 2Y to sleep until the node 2X starts up.

  The sleep instruction unit 310C causes the node 2 that is not connected to the communication path from the control device 300 to the node 2Y to be in the sleep state. As a result, the control device 300 can increase the power storage amount of the node 2Y that is not connected to the communication path to the node 2Y.

  The determining unit 310B calculates an estimated activation date and time of the node 2X based on the prediction result of the battery remaining amount of the node 2X, and determines an acceptance date and time that is a halfway activation date and time of the node 2Y using the estimated activation date and time. As a result, the control device 300 can start the node 2Y at an accurate timing according to the start of the node 2X.

  The reception processing unit 310D sets the node 2X as a reception target from which the node 2Y receives the connection from the nodes 2, based on the halfway activation date and time and the estimated activation date and time. As a result, the control device 300 can set the node 2X with the early estimated start date and time as the accepting target.

  When the connection with the node 2X, which is a child node, is not completed, the reception processing unit 310D sets a node 2X different from the node 2X that could not be connected to the next and subsequent connections as a connection target. As a result, the control device 300 can improve the connection probability with the node 2X.

  If the connection with the node 2X, which is a child node, is not completed, the reception processing unit 310D increases the connection reception time of the node 2Y, which is the connection waiting time for the node 2X that has not been connected for the next and subsequent connections. Let it. As a result, the control device 300 can improve the connection probability with the node 2X.

  The determination unit 310B calculates the estimated activation date and time of the node 2X based on the period from the expected start date and time of the connection attempt of the node 2X to the expected end date and time of the connection trial and the period required for accepting the connection of the node 2X. As a result, the control device 300 can calculate an appropriate estimated activation date and time according to the operation of the node 2X.

  When the environment information 5 is a weather forecast, the communication unit 320 receives the environment information 5 from a wired or mobile phone network. As a result, the control device 300 can appropriately determine the connection acceptance time according to the environment of the node 2.

  The determining unit 310B extracts the node 2 to be the node 2X from the plurality of nodes 2 based on the LQI between the node 2 and the node 2Y. As a result, the control device 300 can attempt to connect to a nearby node 2X within a predetermined distance from the control device 300.

  The environment information 5 includes environmental performance information on the environment up to now and environmental prediction information on the environment in the future. As a result, the control device 300 can appropriately determine the connection acceptance time according to the environment of the node 2X.

  The determination unit 310B calculates a correlation coefficient that is a power characteristic of the node 2X using the ideal power generation amount of the node 2X, the current power storage amount of the node 2X, and the previous power storage amount of the node 2X. As a result, the control device 300 can calculate an accurate correlation coefficient.

  The determination unit 310B acquires a correlation coefficient from the node 2X during the connection before the node 2X is not connected. As a result, even when the node 2X is not connected, the control device 300 can determine the connection acceptance time using the correlation coefficient of the node 2X.

  The communication quality is not limited to LQI, for example, and may be another index. In the above embodiment, when all the connected nodes 2 that have been searched are excluded from the nodes 2 near the accepting node 2, the accepting unit 310D increases the accepting time of the accepting node 2. . However, the reception processing unit 310D may increase the reception time of the reception target node 2 without performing the setting of the neighbor exclusion node. In addition, when some connected nodes 2 that have been searched are set as neighbor exclusion nodes, the reception processing unit 310D may increase the reception time of the reception target node 2.

  Further, in the present embodiment, the control device 300 controls the node 2 using various date and time information such as the connection acceptance date and time. However, the control device 300 may control the node 2 with only time information. .

  In addition, each component of each unit illustrated does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each unit is not limited to the one shown in the figure, and all or a part thereof is functionally or physically distributed / integrated in arbitrary units according to various loads and usage conditions. Can be configured.

  Further, various processing functions performed by each device are executed on a CPU (or a microcomputer such as a micro processing unit (MPU) or a micro controller unit (MCU)) by executing all or any part thereof. Is also good. The various processing functions may be entirely or arbitrarily executed on a program that is analyzed and executed by a CPU (or a microcomputer such as an MPU or an MCU) or on hardware by wired logic. Needless to say.

Reference Signs List 1 control system 2 node 5 environment information 300 control device 310 control unit 310A connection processing unit 310B determination unit 310C sleep instruction unit 310D acceptance processing unit 320 communication unit 330 storage unit 330A unconnected node information storage unit 330B connection node information storage unit 330C node State storage unit 330D Environment information storage unit

Claims (14)

A communication unit that receives information from the first node using multi-hop communication between a plurality of nodes including a connected first node and an unconnected second node;
The remaining battery level of the first node, the communication quality between the first node and the second node, the power characteristics of the second node, and the second node are arranged. A determining unit that determines an acceptance date and time at which the first node accepts a connection with the second node based on first environment information relating to a location environment;
A sleep instructing unit that instructs the first node to put the first node into a sleep state until the reception date and time;
A control device comprising: The sleep instruction unit,
The control device according to claim 1, wherein the control device is configured to instruct the third node to put a third node that is not arranged in a communication path from the control device to the second node into a sleep state. . The determining unit includes:
A battery remaining amount of the second node is predicted based on the power characteristic of the second node and second environment information on an environment at a position where the second node is located, and The control device according to claim 1, wherein an estimated start date and time of the second node is calculated based on the estimated start date and time, and the acceptance date and time are determined using the estimated start date and time.   The apparatus according to claim 1, further comprising: an acceptance processing unit that sets a first acceptance target from which the first node accepts a connection from among the second nodes based on the acceptance date and time and the estimated activation date and time. 3. The control device according to 3. The reception processing unit,
If the connection with the second node is not completed at the reception date and time, a second reception target different from the first reception target is set for the next and subsequent connections. Item 5. The control device according to Item 4. The reception processing unit,
If the connection with the second node is not completed at the reception date and time, the connection reception period of the first node with respect to the second node whose connection has not been completed for the next and subsequent connections is set. The control device according to claim 4, wherein the control device is increased. The determining unit includes:
Based on the prediction result and the first power consumption in a state where the second node is not operating, estimate a predicted start date and time at which the second node can start a connection attempt,
Based on the prediction result and the second power consumption in a state where the second node is trying to connect, an estimated end date and time at which the second node ends the connection attempt is estimated.
The method according to claim 3, wherein the estimated start date and time are calculated based on the expected start date and time, the expected end date and time, and a time required for the first node to accept connection of the second node. The control device as described. The first environmental information is a weather forecast,
The control device according to claim 1, wherein the communication unit receives the weather forecast from a wired or mobile phone network. The determining unit includes:
The control device according to claim 1, wherein the second node is extracted from the plurality of nodes based on a communication quality between the plurality of nodes and the first node. The second environmental information includes:
The control device according to claim 3, wherein the control device includes environmental performance information relating to a previous environment and environmental prediction information relating to a future environment. The determining unit includes:
Calculating the power generation amount of the first node based on the environmental performance information;
The power characteristic of the first node is calculated using the power generation amount of the first node, the current power storage amount of the first node, and the previous power storage amount of the first node power generation amount. The control device according to claim 10, wherein:   The said determination part acquires the electric power characteristic of the said 2nd node from the said 2nd node during the connection before the said 2nd node becomes unconnected, The said 1st characterized by the above-mentioned. The control device according to any one of the above. A plurality of nodes including a first node and a second node;
A control device for controlling the plurality of nodes,
The control device includes:
A communication unit that receives information from the first node using multi-hop communication between the plurality of nodes;
The remaining battery level of the first node, the communication quality between the first node and the second node, the power characteristics of the second node, and the second node are arranged. A determining unit that determines an acceptance date and time at which the first node accepts a connection with the second node based on first environment information relating to a location environment;
A sleep instructing unit that instructs the first node to put the first node into a sleep state until the reception date and time;
A control system comprising: Receiving information from the first node using multi-hop communication between a plurality of nodes including a connected first node and an unconnected second node;
The remaining battery level of the first node, the communication quality between the first node and the second node, the power characteristics of the second node, and the second node are arranged. Determining an acceptance date and time at which the first node accepts a connection with the second node, based on first environment information relating to a location environment;
Instructing the first node to put the first node into a sleep state until the reception date and time;
A control method characterized by executing processing.

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