Radio communication reproducing system

Abstract

To provide a radio communication reproducing system that enables analysis of operation conditions by adding a wireless communication function to discrete event analysis three-dimensional simulation software that can analyze factory environment in a virtual space.SOLUTION: In a system, a radio communication reproducing system unit includes: an advance setting unit which configures, in advance, at least arrangements of objects including a base station and an AGV (Automatic Guided Vehicle), property settings and settings for a radio wave intensity acquisition method, as initial setting information necessary for reproducing radio communication on a three-dimensional model; a heatmap display unit which displays a heatmap of radio wave intensities of the objects using the initial setting information set by the advance setting unit; a wireless communication AGV service range display unit which estimates and displays a service range of the AGV; and a determination unit which determines whether communication connection between the base station and the AGV can be established at a designated timing, based on the estimated service range.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a wireless communication reproduction system, and more particularly to a wireless communication reproduction system for a discrete event analysis three-dimensional simulation system.

Background Art

[0002] The use of wireless communication in factories is progressing, and wireless communication is being introduced not only for control signals and sensor information but also for monitoring manufacturing processes. The concept of IoT (Internet of Things), which transmits and accumulates the aggregated information in the Internet space to create new value, has also become widespread. As the next step, a cyber-physical system (CPS) that processes and analyzes the information obtained in the real world and provides data has attracted attention. A smart factory that realizes the above concept in a factory is considered an essential technology for Japan, where a decrease in population is expected in the future. To realize a simulator that can pre-verify a wireless system in a factory environment, it is necessary to add the function of a wireless communication system to discrete event analysis that can analyze operating conditions in a virtual factory environment.

[0003] Simulators for analyzing operating conditions in a virtual factory environment are sold as software by several companies. In recent years, technologies have been proposed that collect information from factories in the real space, construct a parallel control simulation platform equivalent to the factory floor in a factory constructed in the virtual space, and perform various performance analyses and execution optimizations of equipment (Patent Document 1). Information collection and remote control via a network have also been devised.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional technology does not consider optimization simulations that take into account the use of wireless communication systems as a means of communication within a virtual factory, and there is a problem in that it is not possible to perform optimization within a factory that takes into account the characteristics of wireless communication devices when considering a wireless communication system, or how to handle communication failures and retransmission processes.

[0006] The present invention has been devised in light of the above-mentioned background, and its purpose is to provide a wireless communication reproduction system that enables analysis of operating conditions in a factory environment that includes wireless communication functions by adding wireless communication functions to discrete event analysis three-dimensional simulation software that can analyze operating conditions in a virtual factory environment. [Means for solving the problem]

[0007] The wireless communication reproduction system according to the first invention is a wireless communication reproduction system for a discrete event analysis three-dimensional simulation system, and is characterized by comprising: a pre-setting means for setting in advance the placement of objects representing terminals including base stations and wireless communication AGVs (Automatic Guided Vehicles), property settings for the objects, and settings for radio wave intensity acquisition methods, as initial setting information required to reproduce wireless communication on a three-dimensional model of a virtual space; a first display means for displaying a heat map of the radio wave intensity of the objects on the three-dimensional model using the initial setting information set by the pre-setting means; a second display means for estimating the communication range of the wireless communication AGV traveling on the three-dimensional model and displaying it on the three-dimensional model; and a determination means for determining whether a communication connection between the base station and the wireless communication AGV is possible at a specified timing on the three-dimensional model based on the estimated communication range.

[0008] The wireless communication reproduction system according to the second invention, in the first invention, the presetting means includes an object placement unit that places the objects according to the wireless communication environment to be reproduced, and among the placed objects, at least an object property setting unit that sets the property of the communication characteristics of the terminal including the base station and the wireless communication AGV, a measured data mode that obtains the received radio wave intensity at a certain point by interpolation from the measured data, and a radio wave intensity acquisition method setting unit that sets a calculation formula mode that calculates from the following formula (1) using the data input by the user. The received radio wave intensity Prx(d,f)=Ptx - 10αlog 10 (d) - β - 10γlog 10 (f) - N(0,δ)··(1) Here, let the received radio wave intensity of the terminal be Prx, the transmission power of the base station be Ptx, the distance between the base station and the terminal be d, the radio frequency between the base station and the terminal be f, the random number of the normal distribution be N(0,σ), and the coefficients be α, β, and γ. It is characterized by having a data import unit that imports parameter data of communication characteristics from a data table showing the characteristic data of the communication system.

[0009] The wireless communication reproduction system according to the third invention, in the second invention, the data import unit is characterized in that, in the case of the measured data mode, it imports at least the radio wave intensity measurement point data and the received radio wave intensity data.

[0010] The wireless communication reproduction program according to the fourth invention is a wireless communication reproduction program for a discrete event analysis three-dimensional simulation system, and as initial setting information necessary for reproducing wireless communication on a three-dimensional model of a virtual space, at least the arrangement of objects indicating terminals including base stations and wireless communication AGVs (Automatic Guided Vehicles), property settings of the objects, and a pre-setting step of pre-setting a radio wave intensity acquisition method, a first display step of displaying a heat map of the radio wave intensity of the objects on the three-dimensional model using the initial setting information set by the pre-setting step, a second display step of estimating the communicable range of the wireless communication AGV traveling on the three-dimensional model and displaying it on the three-dimensional model, and a determination step of determining whether communication connection between the base station and the wireless communication AGV is possible at a specified timing on the three-dimensional model based on the estimated communicable range. It is characterized by comprising these steps.

Effect of the Invention

[0011] According to the present invention having the above-described configuration, by adding a wireless communication function to discrete event analysis three-dimensional simulation software capable of analyzing operating conditions in a factory environment of a virtual space, a wireless communication reproduction system capable of analyzing operating conditions in a factory environment including a wireless communication function can be realized.

Brief Description of the Drawings

[0012]

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Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments exemplified by applying the present invention will be described with reference to the drawings.

[0014] FIG. 1 is a functional block diagram of a discrete event analysis three-dimensional simulation system according to an embodiment of the present invention.

[0015] As shown in FIG. 1, the discrete event analysis three-dimensional simulation system 1 includes a basic module unit 11, a geographic information system cooperation unit 12, a human flow verification unit 13, an interference area check unit 14, a database cooperation unit 15, an experimental tool unit 16, an optimizer unit 17, and a wireless communication reproduction system unit 20.

[0016] The basic module unit 11 includes a function-based standard library 110, a dashboard unit 111, and a modeling unit 112, and realizes basic functions.

[0017] The function-based standard library 110 has standard data prepared for 3D objects according to their roles. The present invention has a configuration that allows adding a wireless communication reproduction library for reproducing wireless communication.

[0018] The dashboard unit 111 is equipped with a GUI interface and displays information such as the operating status and output of facilities with various layouts in chronological order in conjunction with simulations, making it visible.

[0019] The modeling unit 112 allows the user to define a unique simulation model in three ways: arranging 3D objects, creating with a UI like a flowchart, and programming by writing code.

[0020] The geographic information system cooperation unit 12 utilizes SCM data to optimize domestic and global logistics in cooperation with GIS and the intervals of parts deliveries.

[0021] The human flow verification unit 13 performs human flow verification in medical fields, airports, large commercial facilities, etc., and can create a human flow simulation in a short time.

[0022] The interference area check unit 14 performs a human flow simulation after specifying the range of social distance (the physical distance between people) for people.

[0023] The database cooperation unit 15 can reflect actual performance data in simulations by cooperating with a production management system or a warehouse management system.

[0024] The experimental tool unit 16 has a function for considering the optimization of the arrangement and number of machines, workers, etc. with respect to the target production quantity.

[0025] The optimizer unit 17 is an AI simulation optimization engine built using algorithm analysis techniques such as metaheuristic optimization, genetic algorithm, tabu search, and scatter search.

[0026] The wireless communication reproduction system unit 20 is software with the characteristic functions of the present invention. It is a function added to the discrete event analysis 3D simulation system 1 and is a plug-in tool that adds wireless communication reproduction functionality. The basic module unit 11, geographic information system linkage unit 12, human movement path verification unit 13, interference area check unit 14, database linkage unit 15, experiment tool unit 16, and optimizer unit 17 of the discrete event analysis 3D simulation system 1 are the same as those of conventional systems. The following describes FlexSim (registered trademark) as an example of the discrete event analysis 3D simulation system 1, but is not limited to this. In addition to queuing simulation functions, FlexSim (registered trademark) has functions such as deriving the shortest travel path using the A* algorithm and multi-agent simulation functions. It also has functions for optimal parameter search using a genetic algorithm and linking with a reinforcement learning engine. Figure 2 shows an example of a 3D model of a smart factory built using FlexSim (registered trademark) as an example of the discrete event analysis 3D simulation system 1.

[0027] Furthermore, the discrete event analysis three-dimensional simulation system 33 may be provided with a radio wave emulator linking unit 34 that links with the radio wave emulator 32, as shown in Fig. 3. The radio wave emulator 32 may then reproduce various simulated wireless systems and radio wave propagation channels that are close to the real environment on the three-dimensional model 31 of the smart factory in the virtual space, and the obtained output results may be passed to the radio wave emulator linking unit 34 as data in CSV format, for example. Here, the radio wave emulator refers to a system that reproduces the propagation of radio waves from wireless devices, buildings, etc. in the virtual space, thereby enabling the verification of wireless devices.

[0028] FIG. 4 is a functional block diagram of a wireless communication reproduction system 20 according to an embodiment of the present invention.

[0029] As shown in Figure 4, the wireless communication reproduction system 20 has a pre-setting unit 21, a heat map display unit 22 as a first display unit, a wireless communication AGV communication range display unit 23 as a second display unit, and a judgment unit 24.

[0030] FIG. 4(b) shows a base station 101, a relay station 102, a terminal 103, and a wireless communication AGV 103a arranged on a three-dimensional model 100 of a virtual space.

[0031] The presetting unit 21 performs in advance the placement of objects representing terminals 103 including the base station 101 and wireless communication AGV (Automatic Guided Vehicle) 103a, property settings for the objects, and settings for radio wave intensity acquisition methods, as initial setting information required to reproduce wireless communication on the three-dimensional model 100 of the virtual space. The terminal 103 is a general term for objects that communicate with the base station 101, and refers to five types of objects: the wireless communication AGV 103a, wireless communication operator, wireless communication processor, wireless communication combiner, and wireless communication separator.

[0032] The heat map display unit 22 serves as a first display unit, and displays a heat map of radio wave intensity of objects on the three-dimensional model 100 using the initial setting information set by the presetting unit 21. It displays a heat map of radio wave intensity of objects such as the base station 101, relay station 102, terminal 103, and walls as obstacles.

[0033] The AGV communication range display unit 23 serves as a second display unit, and estimates the communication range of the wireless communication AGV 103 a traveling on the three-dimensional model 100 and displays it on the three-dimensional model 100 .

[0034] The determination unit 24 determines whether or not a communication connection between the base station 101 and the wireless communication AGV 103a is possible at a specified timing on the three-dimensional model 100 based on the estimated communication range.

[0035] FIG. 5 is a process flowchart of the wireless communication reproduction system 20 according to the embodiment of the present invention.

[0036] As shown in FIG. 5, the processing flow of the wireless communication reproduction system 20 includes a presetting step 301, a first display step, a second display step 303, an AGV setting step 304, and a communication step 305.

[0037] The pre-setting step 301 is a step in which the initial setting information required to reproduce wireless communication on the three-dimensional model 100 of the virtual space is set in advance, including at least the placement of objects representing terminals including base stations and wireless communication AGVs (Automatic Guided Vehicles), property settings for the objects, and settings for the radio wave intensity acquisition method.

[0038] The first display step 302 is a step of displaying a heat map of the radio wave intensity of the object on the three-dimensional model 100 using the initial setting information set in the presetting step 301 .

[0039] The second display step 303 is a step of estimating the communication range of the wireless communication AGV 103 a traveling on the three-dimensional model 100 and displaying it on the three-dimensional model 100 .

[0040] The determination step 304 is a step for determining whether or not a communication connection between the base station 101 and the wireless communication AGV 103a is possible at a specified timing on the three-dimensional model 100 based on the estimated communication range.

[0041] Fig. 6(a) is a functional block diagram of the presetting unit 21 according to the embodiment of the present invention, and Fig. 6(b) is a processing flowchart of the presetting unit 21 according to the embodiment of the present invention. The following description will be made with reference to Fig. 6.

[0042] As shown in FIG. 6(a), the presetting unit 21 includes an object placement unit 25, an object property setting unit 26, a radio wave intensity acquisition method setting unit 27, and a data import unit .

[0043] The object placement unit 25 places objects according to the wireless communication environment to be reproduced.

[0044] The object property setting unit 26 sets properties of the communication characteristics of at least the base station and the terminals including the wireless communication AGV among the placed objects.

[0045] As shown in FIG. 7, the received radio wave intensity acquisition method setting unit 27 sets between a measured data mode of obtaining the received radio wave intensity at a certain point by interpolation from measured data and a calculation formula mode of calculating from the following formula (1) using data input from the user. Received radio wave intensity Prx(d,f)=Ptx - 10αlog 10 (d) - β - 10γlog 10 (f) - N(0,δ) ··· (1) Here, let the received radio wave intensity of the terminal be Prx, the transmission power of the base station be Ptx, the distance between the base station and the terminal be d, the radio frequency between the base station and the terminal be f, the random number of the normal distribution be N(0,σ), and the coefficients be α, β, and γ. FIG. 8(a) shows an example of a two-dimensional map display of the received radio wave intensity in the measured data mode. FIG. 8(b) shows an example of a two-dimensional map display of the received radio wave intensity in the calculation formula mode.

[0046] As shown in FIG. 9, in the calculation formula mode, the received radio wave intensity acquisition method setting unit 27 also corresponds to the directional antenna pattern, inputs data from the outside, or approximates with elementary functions to obtain the received radio wave intensity by the following formula (2), thereby obtaining a result closer to reality. Received radio wave intensity Prx(d,f,θ,φ)=Ptx + Gtx(θ,φ) + Grx(θ,φ) - 10αlog 10 (d) - β - 10γlog 10 (f) - N(0,δ) ··· (2) Here, let the received radio wave intensity of the terminal be Prx, the antenna gain of the terminal be Grx, the transmission power of the base station be Ptx, the antenna gain of the base station be Gtx, the distance between the base station and the terminal be d, the radio frequency between the base station and the terminal be f, the random number of the normal distribution be N(0,σ), and the coefficients be α, β, and γ.

[0047] Hereinafter, the radio wave intensity acquisition method setting unit 27 will be described in detail.

[0048] When the visualization mode of the radio wave intensity is the measured data mode, as shown in FIG. 7, data is imported from the outside. For example, data obtained by actual measurement, data obtained by a radio wave emulator by radio wave propagation simulation, data input in text format, etc. can be used. The probabilistic variation of the radio wave intensity can be set. When not considering the variation of the radio wave intensity, if "no variation" is selected, the received radio wave intensity of the terminal 103 will always be constant according to the measured data. The probability distribution can be set for each of the line-of-sight (LOS) and non-line-of-sight (NLOS) cases. There are two configurable probability distributions: the normal distribution and the extreme value distribution. After setting the probability distribution followed by the variation of the radio wave intensity, the parameter σ representing the amplitude of the probability distribution is set. The probability distribution is defined as follows. Here, μ represents the value of the radio wave intensity when not considering the probability variation. The normal distribution indicates a normal distribution with mean μ and standard deviation σ. The extreme value distribution is a distribution whose probability density function is represented by Equation (3).

[0049]

Equation

[0050] The data import unit 28 imports parameter data of communication characteristics from a data table showing characteristic data of the communication system. As shown in FIG. 10(a), a correspondence table of received radio wave strength, bit error rate, communication speed, etc. may be input in text format according to the wireless system being used. In this way, it is possible to display a map of bit error rate and communication speed based on received radio wave strength. FIG. 10(b) shows an example of a two-dimensional map display of PER when 16QAM is used as the modulation method. FIG. 10(c) shows an example of a two-dimensional map display of communication speed when 16QAM is used as the modulation method.

[0051] Furthermore, adaptive modulation may be used, which switches modulation methods depending on communication conditions that change over time. For example, as shown in Fig. 11, adaptive modulation unit 91 (modified due to duplication of 101) can input information such as delay spread in addition to received power and select the optimal modulation method. For example, QPSK, 16QAM, 64QAM, 256QAM, etc. can be selected as the modulation method.

[0052] The object placement step 401 is a step for placing objects in accordance with the wireless communication environment to be reproduced on the three-dimensional model of the virtual space.

[0053] In object placement step 401, base station objects, repeater objects, terminal objects, and walls are placed. First, the base station object must be placed on the 3D model of the GUI. This is because if the base station 101 is not placed, there will be no object to communicate with the terminal 103, and communication cannot be set up.

[0054] As shown in FIG. 12, repeater objects can be placed as needed. Repeater connections are made between base stations 101 and repeaters 102, or between repeaters 102, forming a network. Here, the network is connected so as to form a tree-type network with the base station as the root. As shown in FIG. 12(a), a tree-type network is formed, which is a good installation example. The example in FIG. 12(b) does not form a tree-type network, i.e., the repeater 102 has two parents, which is a bad installation example. Although the connection of repeaters 102 shows a tree-type network configuration, it may also be formed as a mesh-type network.

[0055] In addition, terminal objects can be placed as necessary. The terminal 103 does not need to establish an A connection with the base station 101 or repeater 102. It will automatically connect to the transmitting station when communication is executed. In addition, when the terminal 103 is placed, an object flow corresponding to that terminal 103 is automatically added to the toolbox. From this object flow, it is possible to set the behavior when communication is successful or when it fails.

[0056] Furthermore, if necessary, you can place a "Wall_Wireless Communication" object as an obstacle. Use the "Wall_Wireless Communication" object instead of the software's default "Wall" object, because the software's default wall object is designed not to recognize radio waves as an obstacle.

[0057] The object property setting step 402 is a step for setting properties of communication characteristics of at least the base station 101 and the terminal 103 including the wireless communication AGV 103a among the arranged objects.

[0058] The property setting item of the base station is condition_id. condition_id is a value indicating which row of the condition data the communication characteristics of the base station object correspond to. Here, the condition data represents the imported data table. The configuration of the condition data table consists of column names and contents, and is composed of the condition_id column, frequency column, tx_point_x column, tx_point_y column, tx_point_z column, txpower_dBm column, tx_ant_gain_dBi column, and rx_ant_gain_dBi column.

[0059] The condition_id column indicates the ID for identifying the data row. The frequency column indicates the frequency used for communication, with the unit being MHz. The tx_point_x column indicates the x coordinate of the transmitting antenna, with the unit being m. The tx_point_y column indicates the y coordinate of the transmitting antenna, with the unit being m. The tx_point_z column indicates the z coordinate of the transmitting antenna, with the unit being m. The txpower_dBm column indicates the transmitted radio wave intensity, with the unit being dBm. The tx_ant_gain_dBi column indicates the transmitting antenna gain, with the unit being dBi. The rx_ant_gain_dBi column indicates the receiving antenna gain, with the unit being dBi.

[0060] The property setting items of the repeater 102 are condition_id and the minimum receivable radio wave intensity for communication. condition_id is the same as that of the base station 101. The minimum receivable radio wave intensity for communication indicates the value used for determining the communication availability with the transmitting station. Specifically, the minimum receivable radio wave intensity for communication is used for the display of the communicable area, the setting of the non-travelable area of the wireless communication AGV103a, and the connection of the terminal 103 to the transmitting station connected in the base station 101.

[0061] The property setting items of the terminal 103 are the minimum received radio wave strength for communication, communication mode, arrival at time 0, and communication time interval. The minimum received radio wave strength for communication indicates the value used to determine whether communication with a transmitting station is possible. Specifically, the minimum received radio wave strength for communication is used to display the communication area, set the area where the wireless communication AGV 103a cannot travel, and when connecting the terminal 103 and the transmitting station. The communication mode is an item for setting the method for specifying the timing of communication execution. There are three communication modes: continuous mode, communication time interval mode, and detailed setting mode in process flow, and one can be selected. Continuous mode specifies that communication should continue to be executed at 0.1 second intervals from the start of the simulation. Communication time interval mode specifies the communication timing as a time interval. Detailed setting mode in process flow sets the communication timing in the process flow.

[0062] The item Arrived at time 0 is displayed only when the communication mode is set to "Communication time interval." If this item is specified, the first communication will occur at the same time as the simulation starts.

[0063] The communication time interval item is displayed only when the communication mode is set to "Communication time interval." Specify the communication time interval.

[0064] The "Wall_Wireless Communication" object does not have any properties that need to be set.

[0065] The radio wave intensity acquisition method setting step 403 is a step for setting either a measured data mode in which the received radio wave intensity at a certain point is obtained by interpolation from measured data, or a calculation formula mode in which the received radio wave intensity is calculated from an arithmetic formula.

[0066] The data import step 404 is a step of importing parameter data of communication characteristics from a data table showing characteristic data of the communication system. In the case of the actual measurement data mode, at least the radio wave intensity measurement point data and the received radio wave intensity data are imported in the data import step 404. In the case of the calculation formula mode, neither the radio wave intensity measurement point data nor the received radio wave intensity data is imported.

[0067] The data table structure of the imported communication system characteristic data consists of the columns Received power (dBm), BER, PER, and Throughput (Mbps). The Received power (dBm) column indicates the value of received signal strength, in dBm units. The BER column indicates the BER value corresponding to the value of received signal strength defined in "Received power (dBm)". The PER column indicates the PER value corresponding to the value of received signal strength defined in "Received power (dBm)". The Throughput (Mbps) column indicates the communication speed value corresponding to the value of received signal strength defined in "Received power (dBm)", in Mbps units. The data file name must be as follows: (Communication system name)_Freq_(center frequency)_BW(bandwidth)_(modulation method)_(any string).csv Example (IEEE802_llax)_Freq_2462MHz)_BW(20MHz)_(16QAM rate3_4)_(Measured_data).csv After importing the data, the communication characteristics parameters are displayed in the bottom right of the dialog on the software GUI. Furthermore, if you switch the tabs on the right side of the dialog to update both sides, the contents of the data table will be displayed as a graph with "Received power (dBm)" on the horizontal axis.

[0068] The data table structure of the imported condition data is as follows: The condition data table consists of column names and contents: condition_id column, frequency column, tx_point_x column, tx_point_y column, tx_point_z column, txpower_dBm column, tx_ant_gain_dBi column, rx_ant_gain_dBi column, and the contents of those columns.

[0069] The data table of the radio wave intensity measurement point data to be imported is composed of column names and contents. The condition_id column is an ID indicating which row of the condition data the measurement point data corresponds to. The rx_id column is an ID for identifying the received radio wave intensity measurement point. The rx_point_x column indicates the x coordinate of the received radio wave intensity measurement point, with the unit being m. The rx_point_y column indicates the y coordinate of the received radio wave intensity measurement point, with the unit being m. The rx_point_z column indicates the z coordinate of the received radio wave intensity measurement point, with the unit being m. Here, when the received radio wave intensity determination method is in the calculation formula mode, the import of this radio wave intensity measurement point data is not required.

[0070] The data table of the received radio wave intensity data to be imported is composed of column names and contents, and is imported from the "rxpower data" tab on the GUI of the software. The condition_id column is an ID indicating which row of the condition data the measurement point data corresponds to. The rx_id column is an ID for identifying the received radio wave intensity measurement point. The rxpower_dBm column indicates the value of the received radio wave intensity at the measurement point specified by rx_id, with the unit being dBm. Here, when the received radio wave intensity determination method is in the calculation formula mode, the import of this radio wave intensity measurement point data is not required.

[0071] The setting items for the heat map display of the radio wave intensity by user input will be described.

[0072] The setting items for the heat map display are the transmission source, the item to be displayed, the heat map maximum value, the heat map minimum value, the legend display interval, set to a height of 0m, move the transmitting station to the position specified in the condition data, heat map calculation / recalculation, display / non - display switching. The transmission source indicates the transmission station object that is the target of heat - mapping the data. An object is directly extracted from the 3D model 100 using the transmission source button.

[0073] For the items to be displayed, select the values to be displayed on the heat map from received signal strength, communication speed, BER, and PER. "Heat map maximum value" sets the value that will be displayed the reddest on the heat map. "Heat map minimum value" sets the value that will be displayed the bluest on the heat map. "Legend display interval" sets how finely the color samples on the color scale are displayed. "Display at 0m height" selects whether or not to force the height at which the heat map is displayed to 0m. "Move transmitting station to position specified by condition data" selects whether or not to move all transmitting stations on the 3D model to the coordinates corresponding to the value of condition_id when the "Calculate / Recalculate heat map" button is pressed. "Calculate / Recalculate heat map" reflects the settings and displays the heat map. "Show / Hide switch" is an item that switches the heat map display on or off.

[0074] When the signal strength determination method for the heat map display is Calculation mode, set the following items: x-coordinate of the first measurement point, y-coordinate of the first measurement point, z-coordinate of the first measurement point, distance between measurement points in the x-direction, distance between measurement points in the y-direction, number of measurement points in the x-direction, and number of measurement points in the y-direction. An image of the first measurement point is shown in Figure 13. The x-coordinate of the first measurement point is the x-coordinate of the first measurement point (= the tile in the heat map with the smallest x-coordinate and y-coordinate values). The y-coordinate of the first measurement point is the y-coordinate of the first measurement point (= the tile in the heat map with the smallest x-coordinate and y-coordinate values). The z-coordinate of the first measurement point is the z-coordinate of the first measurement point (= the tile in the heat map with the smallest x-coordinate and y-coordinate values). The distance between measurement points in the x-direction indicates the distance between measurement points in the x-direction, which corresponds to the width of the heat map tile in the x-direction. The distance between measurement points in the y-direction indicates the distance between measurement points in the y-direction, which corresponds to the width of the heat map tile in the y-direction. The number of measurement points in the X direction indicates the number of measurement points aligned in the X direction, which corresponds to the number of tiles in the heat map aligned in the X direction. The number of measurement points in the y direction indicates the number of measurement points aligned in the y direction, which corresponds to the number of tiles in the heat map aligned in the y direction.

[0075] By setting all of the above required items and pressing the "Heat Map Calculation / Recalculation" button, a heat map of the radio wave intensity is displayed on the 3D model. In the GUI operation, the probabilistic variation of the received radio wave intensity is not considered when the heat map is displayed. That is, the same result is always displayed whenever the heat map is displayed with the same dataset and display settings.

[0076] The setting items when displaying the communicable range are the transmission source object, the reception object, the display range, the display color, display at a height of 0m, move the transmission station to the position specified by the condition data, heat map calculation / recalculation, display / non-display switching.

[0077] The transmission source object sets which transmission station's communicable range is to be displayed. An object is directly extracted from the 3D model using the transmission source button. The reception object sets which receiver device's communicable range is to be displayed. An object is directly extracted from the 3D model using the transmission source button. The display range allows selection of the communicable range setting from only the direct communicable range or including the communicable range via a repeater. The display color allows selection of the color pattern from "communicable in blue, non-communicable in red" or "communicable in white, non-communicable in black". "Display at a height of 0m" allows selection of whether to force the height at which the heat map showing the communicable range is displayed to 0m. "Move the transmission station to the position specified by the condition data" allows selection of whether to move all the transmission stations on the 3D model to the coordinates according to the value of condition_id when the "Heat Map Calculation / Recalculation" button is pressed. "Heat Map Calculation / Recalculation" displays the communicable range reflecting the settings. "Display / Non-display Switching" switches the display / non-display of the communicable range.

[0078] As described above, by setting all the necessary items and pressing the "Heat Map Calculation / Recalculation" button, a map representing the communicable range is displayed on the 3D model. When a repeater is selected as the receiving object, the communicable range is displayed after disconnecting the repeater from the transmitting station network. If it is displayed without disconnection, when the communicable range is defined as "including the communicable range via the repeater", the repeater itself will be included in the available repeaters, and the correct communicable range will not be displayed. Here, the probabilistic variation of the received radio wave intensity is not considered when displaying the communicable range. That is, the same result will always be displayed no matter how many times the communicable range is displayed with the same dataset and display settings.

[0079] The property setting items of the wireless communication AGV103a are "the minimum received radio wave intensity at which the wireless communication AGV can communicate", "display at a height of 0m", "move the transmitting station to the position specified by the condition data", "determine the non-navigable range (create A* barrier)", and "determine the non-navigable range (delete A* barrier)". "The minimum received radio wave intensity at which the wireless communication AGV can communicate" defines that the area where radio waves with an intensity exceeding the value of the minimum received radio wave intensity cannot be received from any transmitting station is the non-navigable area of the wireless communication AGV. "Display at a height of 0m" is to select whether to force the height at which the A* barrier object is placed to 0m. "Move the transmitting station to the position specified by the condition data" is to select whether to move all the transmitting stations on the 3D model to the coordinates corresponding to the value of condition_id when the "Determine Non-navigable Range (Create A* Barrier)" button is pressed. "Determine Non-navigable Range (Create A* Barrier)" is to place A* barrier objects in the non-navigable range after reflecting the settings. "Determine Non-navigable Range (Delete A* Barrier)" is to delete all the barrier objects placed in the non-navigable area of the wireless communication AGV.

[0080] By setting all the necessary items and pressing the "Determine Non-navigable Range (Create A* Barrier)" button, the area where radio waves with an intensity exceeding the value set in "the minimum received radio wave intensity at which the AGV can communicate" cannot be received from any transmitting station is regarded as the non-navigable area of the AGV, and an A* barrier is generated.

[0081] The judgment unit 24 judges whether a communication connection between the base station and the terminal is possible. When a terminal object is placed on the 3D model, the object flow corresponding to that terminal is automatically added to the toolbox. By double-clicking on the menu, the object flow editing screen opens and the user can edit it. Figure 14 shows an overview of the object flow for a wireless communication AGV, and Figure 15 shows an overview of the object flow for terminals other than wireless communication AGVs. In this flow, there are three items named "source" for wireless communication AGVs and two for other terminal objects. This allows the object to communicate with the base station at the specified timing during the simulation.

[0082] Figure 16 shows the object flow for processing when communication with a wireless communication AGV is successful and when it fails. If communication is successful and the object is already stopped, the object is restarted after a delay. In other words, this shows an object flow for restarting movement if communication is successful while the wireless communication AGV is stopped. If communication fails on the way there, if communication fails on the way back, or if there is no connectable transmitting station, if communication fails while the wireless communication AGV is moving, processing can be performed to stop the movement. In the object flow in Figure 16, there are two determination processes after the source, which are performed to ensure that the presence of the wireless AGV is confirmed.

[0083] By rewriting this flow appropriately, you can define the processing to be performed when communication is successful or fails. The token has the following labels set:

[0084] The labels include the FailedTxObj label and the Communicationstate label. When there is a communication failure, the FailedTxObj label stores the object that transmitted the failed communication radio wave. Otherwise, it stores no data. The Communicationstate label stores a string describing the reason for starting this processing flow. Specifically, when the communication is successful, "SUCCESS" is stored; when the outgoing communication fails, "FAIL_OUTWARD" is stored; when the incoming communication fails, "FAIL_RETURN" is stored; when there is no connectable transmitting station, "NO_CONNECTION" is stored; when it is impossible to reach the destination of movement, "ASTAR_ALERT" is stored respectively.

[0085] In the default flow, the following processing is executed. When the communication is successful, if the object is in a stopped state, a restart processing is executed. When the outgoing communication fails, if the object is not in a stopped state, a stop processing is executed. When the incoming communication fails, if the object is not in a stopped state, a stop processing is executed. When there is no connectable transmitting station, if the object is not in a stopped state, a stop processing is executed. When it is impossible to reach the destination of movement, no processing is executed.

[0086] After performing the above settings and running the simulation, the terminal communicates with the base station at the specified timing. The transmitting station currently connected to the terminal is shown as a straight line as in Figure 17. The details of the communication processing will be described.

[0087] (Step 1) Connection between the terminal and the transmitting station First, if the terminal already has a connected transmitting station, it checks the current received radio wave intensity from that transmitting station. If the intensity exceeds the minimum received radio wave intensity at which the terminal can communicate, it continues to connect to that transmitting station. Conversely, if it is below the minimum received radio wave intensity, the connection to that transmitting station is released.

[0088] If there is no connected transmitting station, or if a previously connected station has been disconnected, search for the transmitting station with the strongest received radio wave intensity. If the received radio wave intensity exceeds the minimum receivable radio wave intensity at which the terminal can communicate, connect to that transmitting station. Conversely, if it is below the minimum receivable radio wave intensity, the terminal will not be connected to any transmitting station, and a message containing the string "NO_CONNECTION" in the first parameter will be sent to the terminal.

[0089] (Step 2) Relay of communication from the base station to the terminal If the connection between the terminal and the transmitting station is successful, the base station searches for a route to the transmitting station to which the terminal is connected. If no route is found at this time, an error occurs. If a route is found, communication relay is performed in order according to that route. At this time, for each communication, success or failure is determined with a probability according to the value of the received radio wave intensity. If communication fails somewhere, a message containing the string "FAIL_OUTWARD" in the first parameter is sent from the object that transmitted the failed communication radio wave to the terminal. And the communication process ends there.

[0090] (Step 3) Relay of communication from the terminal to the base station When the communication reaches the terminal, the return communication from the terminal to the base station is executed. Also in this case, for each communication, success or failure is determined with a probability according to the value of the received radio wave intensity. If communication fails somewhere, a message containing the string "FAIL_RETURN" in the first parameter is sent from the object that transmitted the failed communication radio wave to the terminal. And the communication process ends there.

[0091] If the communication reaches the base station successfully, a message containing the string SUCCESS in the first parameter is sent to the terminal.

[0092] The characteristics of the wireless communication system can include radio wave propagation characteristics, interference power characteristics, characteristics of the communication method of the wireless system used, etc.

[0093] While there are methods for measuring radio wave propagation characteristics, they can also be found by constructing a 3D model of the factory and using various electric field analysis methods (ray tracing, FDTD, finite element method, etc.) to consider the characteristics of wireless transmitting stations (transmission output and antenna characteristics), or by using estimation formulas specified in standards such as ITU-R, IEEE, and 3GPP (registered trademark). Figure 8 shows an example of the results of receiving power distribution estimation using estimation formulas. This will reveal the received power of the desired wave at the wireless receiving terminal and the interference power from other wireless stations, and by obtaining delay profile characteristics that show the status of arriving waves, it will be possible to grasp the characteristics of the wireless system in more detail.

[0094] Various types of wireless communication systems are expected to be used within factories, such as 920 MHz band sensor networks, 2.4 GHz / 5 GHz / 60 GHz band wireless LAN, and 4.7 GHz / 28 GHz band local 5G, and by inputting the characteristics of these various wireless systems (minimum receive power for communication, error rate, communication speed, delay, etc.) as a dataset, it is possible to analyze the characteristics of wireless communication systems from the radio wave propagation characteristics mentioned above.In addition, by providing an externally input antenna pattern to the transmitter, it is possible to analyze the characteristics of wireless systems when using directional antennas as well as omnidirectional antennas.

[0095] When remotely controlling mobile robots or AGVs moving around a factory via a wireless network, it is necessary to understand the communication conditions that change over time in order to maintain stable communications.By implementing adaptive modulation, which switches the modulation method according to the communication conditions, it is possible to more accurately predict the communication speed of wireless terminals.

[0096] In addition, in a network configuration where relay stations are installed within the communication range of a base station to establish communication with terminals in non-line-of-sight areas, or in a mesh network configuration where wireless communication terminals are interconnected, it is possible to determine and estimate the communication area from both the base station and the relay station, making it possible for the terminal to estimate the wireless station with the best communication conditions. Examples of this communication range estimation are shown in Figures 18 and 19.

[0097] By enabling wireless communication signals to include sensor information (such as the coordinates of the current location and information on the conveyor's feed speed), it becomes possible to adjust the AGV control and production parameters of factory equipment according to the availability and quality of communication, enabling simulations that are closer to reality.Figure 20 shows an example of a network configuration in which the wireless station with the best communication conditions is selected when this relay station is installed.

[0098] By using FlexSim's (registered trademark) A* algorithm's shortest route search function, it is possible to analyze the shortest route while avoiding areas where communication with both base stations and repeaters is impossible. Figures 21 and 22 show examples of movement analysis for a wireless AGV. This makes it possible to navigate the AGV and workers and move them along the shortest route without communication errors. It is also possible to estimate the time required for movement.

[0099] This invention enables simulations that take into account the characteristics of wireless communication systems, enabling simulations that combine wired and wireless communication paths within a factory. This allows for the creation of a virtual factory environment that integrates wirelessly controlled equipment such as automated guided vehicles (AGVs), information gathering devices such as wireless sensor terminals, and wireless devices such as wireless terminals held by equipment operators. By analyzing the operating status and production volume of the factory environment, this helps to realize a smart factory that achieves more efficient equipment placement and automation within the factory. In particular, by using the optimal parameter search function of FlexSim®, it is possible to find an efficient placement without manual trial and error.

[0100] <Examples of use in which the effects of the invention are most effectively demonstrated> When building a network by connecting multiple wireless terminals, prior verification through simulation is also useful when installing relay stations to expand the communication area, taking into account differences in radio wave propagation characteristics depending on the location of the terminal within the factory.

[0101] This reduces the cost of pre-verification, such as determining the optimal wireless equipment placement when introducing a wireless communication system into a factory, comparing the characteristics of various wireless systems, and designing wiring to build a network that combines wired and wireless connections within a factory.

[0102] Furthermore, this invention is not limited to use within factories, but is also effective for general base station installation studies. For example, by simulating the flow of people carrying wireless communication terminals with buildings and terrain as obstacles, it is possible to study the placement of base stations when establishing a wireless system in a certain area. [Explanation of symbols]

[0103] 1. Discrete Event Analysis 3D Simulation System 11 Basic module section 12 Geographic Information System Collaboration Department 13 People Flow Verification Department 14 Interference area check section 15 Database Linkage Department 16 Experimental Tools Section 17 Optimizer section 20 Wireless Communication Reproduction System Department 21 Presetting section 22 Heat map display 23 Wireless communication AGV communication range display unit 24 Judgment section 25 Object placement section 26 Object property setting section 27 Radio wave acquisition method setting section 28 Data Import Section 31 3D factory model 32 Radio Emulator 33 Discrete Event Analysis 3D Simulation System 34 Radio Emulator Linkage Section 100 3D models of virtual space 101 Base station 102 Relay Station 103 terminals 103a Wireless communication AGV 301 Pre-configuration Steps 302 First display step 303 Second display step 304 Judgment Step 401 Object Placement Step 402 Set Object Property Step 403 Radio wave acquisition method setting step 404 Data Import Step

Claims

1. A wireless communication reproduction system for a discrete event analysis three-dimensional simulation system, comprising: As initial setting information necessary for reproducing wireless communication on a three-dimensional model of a virtual space, at least a pre-setting means for pre-setting the arrangement of objects indicating terminals including a base station and a wireless communication AGV (Automatic Guided Vehicle), the property setting of the objects, and the setting of a radio wave intensity acquisition method; A first display means for displaying a heat map of the radio wave intensity of the object on the three-dimensional model using the initial setting information set by the pre-setting means; A second display means for estimating the communicable range of the wireless communication AGV traveling on the three-dimensional model and displaying it on the three-dimensional model; A determination means for determining whether a communication connection between the base station and the wireless communication AGV is possible at a specified timing on the three-dimensional model based on the estimated communicable range; A wireless communication reproduction system, characterized by comprising the above.

2. The pre-setting means includes: An object arrangement unit for arranging the objects according to the wireless communication environment to be reproduced; [[ID=IO]]An object property setting unit for setting the properties of the communication characteristics of terminals including at least the base station and the wireless communication AGV among the arranged objects; A radio wave intensity acquisition method setting unit for setting a measured data mode in which the received radio wave intensity at a certain point is obtained by interpolation from measured data, and a calculation formula mode in which it is calculated from the following formula (1) using data input by the user. Received radio wave intensity Prx(d, f) = Ptx - 10α log 10 (d) - β - 10γ log 10 (f) - N(0, δ) ··· (1) Here, let the received radio wave intensity of the terminal be Prx, the transmission power of the base station be Ptx, the distance between the base station and the terminal be d, the radio frequency between the base station and the terminal be f, the random number of the normal distribution be N(0,σ), and the coefficients be α, β, γ. A data import unit for importing parameter data of communication characteristics from a data table showing characteristic data of the communication system; The wireless communication reproduction system according to claim 1, characterized by having the above.

3. The data import unit imports at least radio wave intensity measurement point data and received radio wave intensity data in the case of the measured data mode. The wireless communication reproduction system according to claim 2, characterized by the above.

4. A wireless communication reproduction program for a discrete event analysis three-dimensional simulation system, comprising: As initial setting information necessary for reproducing wireless communication on a 3D model of a virtual space, at least a pre-setting step of pre-setting the arrangement of objects indicating terminals including a base station and a wireless communication AGV (Automatic Guided Vehicle), the property settings of the objects, and the setting of a radio wave intensity acquisition method, a first display step of displaying a heat map of the radio wave intensity of the object on the 3D model using the initial setting information set by the pre-setting step, a second display step of estimating the communicable range of the wireless communication AGV traveling on the 3D model and displaying it on the 3D model, a determination step of determining whether a communication connection between the base station and the wireless communication AGV is possible at a specified timing on the 3D model based on the estimated communicable range, A wireless communication reproduction program characterized by comprising the above.

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