Cell control device that controls a manufacturing cell in response to a command from a production management device

Abstract

A cell control device (50) configured to control a manufacturing cell (12) comprising a plurality of machines (20, 22, 24) according to a command from a production management device (14), the cell control device comprising: a communication section (58) configured to communicate with the production management device and the manufacturing cell comprising the plurality of machines, wherein the communication section (58) comprises a first communication section configured to communicate with the production management device (14) and a second communication section configured to communicate with the manufacturing cell (12); a communication controller (62) configured to cause the communication section to perform scheduled communication intended to be performed with the production management device or the plurality of machines; a communication detection section (64) configured to monitor a current communication traffic in the communication section, to compare the current communication traffic performed in a monitoring period with the planned communication traffic of the planned communication scheduled to be performed in the monitoring period, to determine whether the current communication traffic is more than the planned communication traffic, and, if the current communication traffic is more than the planned communication traffic, to detect an unauthorized communication (86, 88, 98, 106, 116); and a communication blocking section (66) configured to block communication in that of the first and second communication sections in which unauthorized communication is detected, to maintain communication in that of the first and second communication sections in which no unauthorized communication is detected, wherein the monitoring period is set to be a period from a start time of a first scheduled communication to a start time of a second scheduled communication executed after the first scheduled communication, and wherein, within the monitoring period, periods in which no communication is planned are predicted by cycle times of work performed by the plurality of machines.

Description

Background of the invention

[0001] The invention relates to a cell control device that controls a manufacturing cell in response to a command from a production management device.

[0002] The prior art knows cell control devices that control a manufacturing cell comprising machines in response to a command from a production management device as a host computer (see, for example, JP 2011 - 186 910 A).

[0003] In this technical field, there is a need for a method for preventing unauthorized communication in which a third party makes unauthorized access to a cell control device.

[0004] The document EP 2 299 650 A1 discloses a technique in which - for anomaly detection in a control network, for example for monitoring and control, industrial or building automation - a technology of an intrusion detection system (IDS) is adapted to analyze a temporal sequence and temporal intervals of correct messages in the network traffic and to use them for training an anomaly detection system.By determining a temporal sequence and rhythm of proper messages, it becomes possible to detect device malfunctions or tampering, as well as attacks carried out using regular observation or control stations that have been hijacked or are defective, and which cannot be detected either by content-based methods (using signatures or byte sequence analysis) or by a significant increase in data traffic. This creates an additional security barrier that can still monitor a technical facility whose control network has already been compromised and protect it (if necessary by alerting security personnel) from potential acts of sabotage. Summary of the invention

[0005] According to the disclosure, cell control devices are provided according to the independent claims. Developments are presented in the dependent claims. Short description of the drawings

[0006] The foregoing or further objects, features and advantages of the invention will become apparent from the description of the following embodiments with reference to the accompanying drawings. Fig. 1 shows a block diagram of a network system according to one embodiment; Fig. 2 shows a timing diagram of the communication traffic in Fig. 1, wherein section (a) shows a timing chart of the scheduled communication traffic between the production management device and the cell control device, section (b) shows a timing chart of the scheduled communication traffic between the cell control device and the manufacturing cell, and sections (c) and (d) each show timing charts of the communication traffic when unauthorized communication overrides the scheduled communication between the cell control device and the manufacturing cell. Fig. 3 shows a timing diagram of the communication traffic between the cell control device and the manufacturing cell according to another example, wherein section (a) shows a timing diagram of the scheduled communication traffic and section (b) shows a timing diagram of the communication traffic when an unauthorized communication overrides a scheduled communication. Fig. 4 shows a timing diagram of the communication traffic between the cell control device and the manufacturing cell according to another example, wherein section (a) shows a timing diagram of the scheduled communication traffic and section (b) shows a timing diagram of the communication traffic when an unauthorized communication overrides a scheduled communication. Fig. 5 shows a timing diagram of the communication traffic between the cell control device and the manufacturing cell according to another example, wherein section (a) shows a timing diagram of the scheduled communication traffic and section (b) shows a timing diagram of the communication traffic when an unauthorized communication overrides a scheduled communication. Detailed description

[0007] Embodiments of the invention are described in detail below with reference to the drawings. First, a network system 10 according to an embodiment of the invention is described with reference to Fig. 1 described.

[0008] The network system 10 is an industrial system for manufacturing a product. The network system 10 includes a manufacturing cell 12, a cell control device 50, a production management device 14, and communication networks 16 and 18.

[0009] The manufacturing cell 12 includes a plurality of machines 20, 22, and 24. Each of the machines 20, 22, and 24 is, for example, an NC machine tool, an industrial robot, or a PLC. The machines 20, 22, and 24 sequentially perform work to manufacture a product according to commands from the cell control device 50. For example, the manufacturing cell 12 is installed in a first building on a factory site for manufacturing the product.

[0010] The cell control device 50 transmits various commands to each of the machines 20, 22, and 24 via the communication network 16 according to a command from the production management device 14 to control the operation of the manufacturing cell 12. For example, the manufacturing cell 50 is installed in a second building, different from the first building, on the factory premises for manufacturing the product. Details of the cell control device 50 are described below.

[0011] The communication network 16 connects the cell control device 50 and the machines 20, 22, and 24 of the manufacturing cell 12 for communication. For example, if the manufacturing cell 12 is installed in the first building and the cell control device 50 is installed in the second building, the communication network 16 consists of an intranet or other LAN.

[0012] The production management device 14 includes, for example, a database and manages the workflow in the manufacturing cell 12 or the material used for the product. The production management device 14 transmits various commands to the cell control device 50 via the communication network 18. For example, the production management device 14 is installed in a third building outside the factory premises for manufacturing the product.

[0013] The communication network 18 connects the production management device 14 and the cell control device 50 for communication. For example, if the cell control device 50 is installed in the second building and the production management device 14 is installed in the third building, the communication network 18 consists of the Internet or the like.

[0014] The cell control device 50 includes a CPU 52, a system memory 54, a working memory 56, a communication section 58, and a timer 60. The CPU 52 performs various calculations to execute various processes to be executed in the cell control device 50.

[0015] The system memory 54 is an electrically erasable and writable non-volatile memory and consists, for example, of an EEPROM® or the like. The system memory 54 records constants, variables, setting values, programs, or the like that are necessary for the operation of the cell control device 50 so that they are not lost when the cell control device 50 is out of operation.

[0016] The main memory 56 is a high-speed read-write RAM and consists of, for example, a DRAM, an SRAM, or the like. The main memory 56 has a storage capacity sufficient for the CPU 52 to perform various calculations.

[0017] The communication section 58 includes, for example, an I / O interface such as a USB port, an Ethernet® port, or the like, and a communication control module configured to control communication via the I / O interface (neither shown). The communication section 58 communicates with the manufacturing cell 12 and the production management device 14 according to a command from the CPU 52.

[0018] The timer 60 clocks an elapsed time from a predetermined time according to an instruction from the CPU 52.

[0019] The following describes the operation of the network system 10 with respect to Fig. 2. Section (a) in Fig. 2 shows a timing diagram of the communication traffic C between the production management device 14 and the cell control device 50. Section (b) in Fig. Figure 2 shows a timing diagram of the communication traffic C between the cell control device 50 and the manufacturing cell 12 (i.e., the machines 20, 22, and 24).

[0020] As shown in section (a), the production management device 14 transmits a production command signal 70 to the cell control device 50 over a period of time t0 to time t1. For example, the production command signal 70 includes a command for "manufacturing 'n' pieces of product A" in the manufacturing cell 12. The production command signal 70 is transmitted from the production management device 14 in a timely manner according to a production plan stored in the production management device 14.

[0021] The production command signal 70 transmitted from the production management device 14 is transmitted to the communication section 58 of the cell control device 50 via the communication network 18.

[0022] The maximum communication speed of the communication network 18 is predetermined according to the structure of the communication network 18. In Fig. In the example shown in Figure 2, the signal is transmitted at the maximum communication speed of the communication network 18. That is, if the production command signal 70 is transmitted at the maximum communication speed of the communication network 18, the time period from time t0 to time t1 is required to transmit the production command signal 70.

[0023] The CPU 52 of the cell control device 50 sends a command to the communication section 58 to cause the communication section 58 to receive the production command signal 70 transmitted from the production management device 14. Thus, in this embodiment, the CPU 52 serves as a communication controller 62 configured to cause the communication section 58 to perform the communication ( Fig. 1). The CPU 52 stores the production command signal 70 received from the communication section 58 in the system memory 54.

[0024] Upon receiving the production command signal 70, the CPU 52 of the cell control device 50 sends a command to the communication section 58 to cause the communication section 58 to transmit a work command signal 72 to the machine 20. The work command signal 72 includes a command to cause the machine 20 to perform a predetermined work based on the production command signal 70 (for example, the command to "manufacture 'n' pieces of product A").

[0025] In section (b) in Fig. 2, the communication section 58 transmits the work command signal 72 to the machine 20 at a maximum communication speed of the communication network 16 over a period of time from time t1 to time t2.

[0026] Upon receiving the work command signal 72, the machine 20 performs the specified work (e.g., processing, welding, and assembling a workpiece) according to the work command signal 72. Upon completion of the specified work, the machine 20 transmits a completion report signal 74 to the communication section 58 of the cell control device 50. In section (b) in Fig. In the example shown in Figure 2, the final report signal 74 is transmitted over a period from a time t3 to a time t4.

[0027] The CPU 52 of the cell control device 50 sends a command to the communication section 58 to receive the completion report signal transmitted from the machine 20 and stores the received completion report signal 74 in the system memory 54.

[0028] Upon receiving the final report signal 74, the CPU 52 of the cell control device 50 sends a command to the communication section 58 to cause the communication section 58 to transmit a work command signal 76 to the machine 22. The work command signal 76 includes a command for causing the machine 22 to perform a predetermined work based on the production command signal 70. In section (b) in Fig. In the example shown in Figure 2, the work command signal 76 is transmitted over a period of time from a time t5 to a time t6.

[0029] Upon receiving the work command signal 76, the machine 22 performs the specified work according to the work command signal 76. Upon completion of the specified work, the machine 22 transmits a completion report signal 78 to the communication section 58 of the cell control device 50. In section (b) in Fig. In the example shown in Figure 2, the final report signal 78 is transmitted over a period from a time t7 to a time t8.

[0030] The CPU 52 of the cell control device 50 sends a command to the communication section 58 to receive the completion report signal transmitted from the machine 22 and stores the received completion report signal 78 in the system memory 54.

[0031] Upon receiving the final report signal 78, the CPU 52 of the cell control device 50 sends a command to the communication section 58 to cause the communication section 58 to transmit a work command signal 80 to the machine 24. The work command signal 80 includes a command for causing the machine 24 to perform a predetermined work based on the production command signal 70. In section (b) in Fig. 2, the work command signal 80 is transmitted over a period of time from a time t9 to a time t 10 transmitted.

[0032] Upon receiving the work command signal 80, the machine 24 performs the specified work according to the work command signal 80. Upon completion of the specified work, the machine 24 transmits a completion report signal 82 to the communication section 58 of the cell control device 50. In section (b) in Fig. 2, the final report signal 82 is transmitted over a period from a time t 11 up to a time t 12 transmitted.

[0033] The CPU 52 of the cell control device 50 sends a command to the communication section 58 to receive the final report signal transmitted from the machine 24 and stores the received final report signal 82 in the system memory 54.

[0034] Upon receiving the completion report signal 82, the CPU 52 of the cell control device 50 sends a command to the communication section 58 to cause the communication section 58 to send a production completion signal 84 to the production management device 14 over a period from time t 12 up to a time t 13 to transfer.

[0035] The production completion signal 84 is a signal indicating that the command contained in the production command signal 70 (for example, "manufacture 'n' pieces of product A") has been completed. Thus, the machines 20, 22, and 24 sequentially execute the specified work according to the production command signal 70, thereby manufacturing the products.

[0036] The provisions in section (a) and (b) in Fig. The timing diagrams shown in Figure 2 are from the communication scheduled for execution by the CPU 52 (hereinafter referred to as "scheduled communication"). The sequence of the scheduled communication is prescribed in a program previously created, for example, by a user.

[0037] The CPU 52 executes the operations described in sections (a) and (b) in Fig. 2 executes the scheduled communication according to the program. The program, the work command signals 72, 76, and 80, and the production completion signal 84 are stored in advance in the system memory 54.

[0038] There may be a risk that a third party may access the cell control device 50 without authorization, which differs from the procedure described in sections (a) and (b) in Fig. 2 shows the planned communication.

[0039] To solve this, the cell control device 50 according to this embodiment monitors the current communication traffic Ca in communication section 58, compares the current communication traffic C a with the planned communication traffic C p in section (a) and (b) in Fig. 2 and determines whether the current communication traffic C a is more than the planned communication traffic C p , which detects unauthorized communication by a third party.

[0040] Below, this function is related to section (c) in Fig. 2. In the example shown in section (c), unauthorized communication 86 occurred by accessing the communication section 58 via the communication network 16 in the period from time t4 to time t5. The CPU 52 constantly monitors the current communication traffic C a the communication which the CPU 52 commands the communication section 58 to carry out.

[0041] For example, the cell control device 50 determines in real time whether a communication traffic is detected in the communication section 58 within a period in which the CPU 52 is not performing scheduled communication. For example, in the case shown in section (c) in Fig. 2, the period in which the planned communication is not to be carried out, each of the periods from t2 to t3, from t4 to t5, from t6 to t7, from t8 to t9 and from t 10 are 11 .

[0042] The CPU 52 sends a command to the timer 60 at a time t n (that is, at time t2, t4, t6, t5, t 10 or t 12 ), to which a planned communication P n (i.e., a communication of signal 72, 74, 76, 78, 80 or 82) has been completed by an elapsed time from time t n to clock.

[0043] In this regard, a period T A from time t nbe predicted when a planned communication P n at a time t n+1 is completed when the next scheduled communication P n+1 to execute after the one planned communication P n is started (that is, T A = t n+1 - t n ). In particular, cycle times of work performed by machines 20, 22, and 24 are predictable. Accordingly, a period from a time when CPU 52 completes the transmission of each of work command signals 72, 76, and 80 to a time when each of completion report signals 74, 78, and 82 is output can be predicted.

[0044] If the communication traffic C is detected in real time in the communication section 58 until the elapsed time clocked by the timer 60 from time t nreaches a predetermined time τ1, the CPU 52 determines in real time that the current communication traffic C a in communication section 58 is more than the planned communication traffic C p .

[0045] The predetermined time τ1 is determined in advance as a time that corresponds to the predicted period T A (that is, τ1 = T A ), and is stored in the system memory 54. When performing a process for detecting unauthorized communication, the CPU 52 reads the time τ1 stored in the system memory 54 and stores the time τ1 in the working memory 56 for reference.

[0046] In section (c) in Fig. 2, the CPU 52 determines in real time whether the communication traffic C is detected in the communication section 58 until the time τ1 (for example, corresponding to the period from time t4 to time t5) of each of the times t2, t4, t6, t8, t 10 and t 12 has expired.

[0047] As a result, the CPU 52 detects that there is communication traffic in the communication section 58 in the period from time t4 to time t5 in which no communication is scheduled, and thus determines in real time that the current communication traffic C a in communication section 58 is more than the planned communication traffic C p As a result, the CPU 52 can detect the unauthorized communication 86 that occurred in the period from time t4 to time t5 in real time.

[0048] Thus, in this embodiment, the CPU 52 serves as a communication detection section 64 ( Fig. 1), which is designed to determine whether the current communication traffic C a is more than the planned communication traffic C p .

[0049] When the CPU 52 detects the unauthorized communication 86 via the communication network 16, the CPU 52 sends a command to the communication section 58 to block communication between the communication section 58 and the communication network 16 over which the unauthorized communication occurred. This can prevent the third party from performing unauthorized access to the cell control device 50 via the communication network 16.

[0050] Thus, in this embodiment, the CPU 52 serves as a communication blocking section 66 ( Fig. 1), which is designed to block communication by the communication section 58.

[0051] However, the CPU 52 does not block communication between the communication section 58 and the communication network 18 in which no unauthorized communication 86 has been detected. According to this configuration, since communication continues via the communication network 18 in which the unauthorized communication 86 has not been detected, at least some of the functions of the cell control device 50 can be continuously executed even if the unauthorized communication 86 is detected.

[0052] As another example, the CPU 52 may send a command to the timer 60 at a time t1, t3, t5, t7, t9, or t 11 ) at the start of a planned communication P n (that is, signal 72, 74, 76, 78, 80 or 82) to determine an elapsed time from time t n-1 to clock.

[0053] Below is this example in relation to section (d) in Fig. 2. In section (d) in Fig. In the example illustrated in Figure 2, an unauthorized communication 88 is performed via the communication network 16 due to unauthorized access to the communication section 58, so that it partially overrides the scheduled communication of the work command signal 76. As a result, the scheduled communication of the work command signal 76, which began at time t5, is extended until a time t6' (>t6) by the unauthorized communication 88, which overrides it.

[0054] In this example, the CPU 52 determines in real time whether a communication traffic in the communication section 58 has occurred within a period of time when the elapsed time from time t n-1 to start a planned communication P n a given time τ2 passes until a time when this elapsed time reaches a time τ3 is recorded.

[0055] In this regard, a period T B from time t n-1to start a planned communication P n until time t n+1 to the start of the next scheduled communication P n+1 to execute after the one planned communication P n be predicted (that is, T B = t n+1 - t n-1 ). In particular, the cycle times of operations performed by machines 20, 22, and 24 are predictable as previously described.

[0056] In addition, a time required for the communication of the signal 72, 74, 76, 78, 80 or 82 can also be predicted from an information amount (total communication traffic) of each of these signals, which is determined depending on a time format, etc., of this and the communication speed of the communication network 16. From such information, the time period T B predictable.

[0057] The predetermined time τ2 is determined in advance as a time that coincides with a time predicted to be required for the communication of the signal 72, 74, 76, 78, 80 or 82 (for example, τ2 = t2 - t1) and is stored in the system memory 54.

[0058] Furthermore, the given time τ3 is defined in advance as a time constant corresponding to the predicted period T B matching time (i.e. τ3 = T B ) and stored in the system memory 54. When performing a process for detecting unauthorized communication, the CPU 52 reads the times τ2 and τ3 stored in the system memory 54 and stores the times τ2 and τ3 in the working memory 56 for reference.

[0059] In section (d) in Fig. 2, the CPU 52 begins clocking the elapsed time by the timer 60 at each of the times t1, t3, t5, t7, t9 and t 11and determines in real time whether a current communication traffic is detected in the communication section 58 within a period in which the elapsed time falls within the period from time τ2 to time τ3 (for example, corresponding to the period from time t6 to time t7).

[0060] As a result, the CPU 52 detects that the communication traffic in the communication section 58 is present in the period from time t6 to time t7 in which no communication is scheduled, and thus determines in real time that the current communication traffic C a in communication section 58 is more than the planned communication traffic C p As a result, unauthorized communication 88 can be detected in the period from t6 to t7.

[0061] Upon detecting the unauthorized communication 88, the CPU 52 serves as a communication blocking section 66 to block communication between the communication section 58 and the communication network 16 over which the unauthorized communication 88 occurred.

[0062] The provisions in section (d) in Fig. The unauthorized communication 88 illustrated in FIG. 2 may begin before time t5, so that it overlaps the work command signal 76. Even in such a case, the CPU 52 can detect the unauthorized communication 88 by the method according to this example.

[0063] A communication for confirming a work progress status may be performed as a scheduled communication between the cell control device 50 and the machines 20, 22 and 24 within a period of time when the time specified in section (b) in Fig. 2 is sent at a time when the completion report signal 74, 78, 82 is received.

[0064] Such an example is given below in relation to Fig. 3 described. Fig. 3 shows a period between the work command signal 72 and the completion report signal 74 as an example.

[0065] As stated in section (a) in Fig. 3, after transmitting the work command signal 72, the CPU 52 sends a command to the communication section 58 at a time t 21 to transmit the communication section 58 for transmitting a first progress confirmation signal 90 to the machine 20. In section (a) in Fig. 3, the communication section 58 transmits the first progress signal 90 to the machine 20 over a period from time t 21 up to a time t 22 .

[0066] When the machine 20 receives the first progress confirmation signal 90, it transmits a first progress report signal 92 indicating a progress status of a work currently being performed by the machine 20 to the communication section 58 of the cell control device 50. In section (a) in Fig. 3, the first progress report signal 92 is transmitted over a period from a time t 23 up to a time t 24 transmitted.

[0067] The CPU 52 causes the communication section 58 to receive the first progress report signal 92 transmitted from the machine 20 and stores the received first progress report signal 92 in the system memory 54.

[0068] Upon receipt of the progress report signal 92, the CPU 52 sends a command to the communication section 58 to cause the communication section 58 to send a second progress confirmation signal 94 to the machine 20 over a period of time t 25 up to a time t 26 to transfer.

[0069] When the machine 20 receives the second progress confirmation signal 94, it transmits a second progress report signal 96 indicating the progress status of a work currently being performed by the machine 20 to the communication section 58 of the cell control device 50 over a period of time t 27 up to a time t 28 .

[0070] The CPU 52 of the cell control device 50 causes the communication section 58 to receive the second progress report signal 96 transmitted from the machine 20 and stores the received second progress report signal 96 in the system memory 54. The CPU 52 can derive the progress status of the work by the machine 20 from the detected first progress report signal 92 and second progress report signal 96.

[0071] The scheduled communication of the first progress confirmation signal 90, the first progress report signal 92, the second progress confirmation signal 94, and the second progress report signal 96 as previously described may similarly be performed within a period between the work command signal 76 and the completion report signal 78 and a period between the work command signal 80 and the completion report signal 82.

[0072] Thus, in this example, the CPU 52 performs scheduled communication for confirming the progress status of the work (i.e., communication of signals 90, 92, 94, and 96) during the period from the transmission of the work command signal 72, 76, 80 to the receipt of the completion report signal 74, 78, 80. The sequence of this scheduled communication is prescribed in a program previously created, for example, by a user.

[0073] The following is with regard to section (b) in Fig. 3 the function for detecting unauthorized communications when performing the functions described in section (a) in Fig. 3 described communication.

[0074] In section (b) in Fig. 3, an unauthorized communication 98 is carried out due to unauthorized access to the communication section 58 via the communication network 16, so that it partially overrides the planned communication of the first progress report signal 92. As a result, the communication at time t 23 started planned communication of the first progress report signal 92 up to a time t 24 ' (>t 24 ) is extended by the unauthorized communication 98, which overlays it.

[0075] The CPU 52 may similarly detect the unauthorized communication 98 by the method for detecting the unauthorized communication 88 of section (d) in Fig. 2 as described above. In particular, the CPU 52 determines in real time whether a communication traffic in the communication section 58 has occurred within a period of time when the elapsed time from time t m to start a planned communication Pn (i.e., a scheduled communication of the signal 72, 90, 92, 94, or 96) passes a predetermined time τ4 until a time when this elapsed time reaches a time τ5 is detected.

[0076] In this regard, a period T c from time t m to start a planned communication P m up to a time t m+1 to the start of the next scheduled communication P m+1 to execute after the one planned communication P m be predicted (that is, T c = t m+1 - t m ). Furthermore, a signal 72, 90, 92, 94, or 96 can also be predicted for communication.

[0077] The predetermined time τ4 is determined in advance as a time that coincides with a time predicted to be required for the communication of the signal 72, 90, 92, 94, or 96 (for example, τ4 corresponds to t 24 -t 23) and stored in the system memory 54. Furthermore, the predetermined time τ5 is determined in advance as a time constant corresponding to the predicted period Tc (i.e., τ5 = T c ) matching time is determined and stored in the system memory 54.

[0078] The CPU 52 begins clocking the elapsed time by the timer 60 at each of the times t1, t 21 , t 23 , t 25 and t 27 to the start of the scheduled communication of the signals 72, 90, 92, 94 and 96. Subsequently, the CPU 52 determines whether a communication traffic is detected in the communication section 58 in a period in which the elapsed time clocked by the timer 60 is in a range of τ4-τ5 (for example, corresponding to the period from time t 24 until time t 25 ).

[0079] As a result, the CPU 52 detects that communication traffic in the communication section 58 within the period from time t24 until time t 25 in which no communication is planned, and thus determines in real time that the current communication traffic C a in communication section 58 is more than the planned communication traffic C p . As a result, the CPU 52 can detect the unauthorized communication 98 in the period of t 24 are 25 capture.

[0080] When the unauthorized communication 98 is detected, the CPU 52 serves as a communication blocking section 66 to block communication between the communication section 58 and the communication network 16 through which the unauthorized communication 98 was made.

[0081] In addition to the scheduled communication of the previously described work command signals, completion report signals, progress confirmation signals, and progress report signals, the CPU 52 may regularly perform other scheduled communication for acquiring various types of information from the machines 20, 22, and 24.

[0082] The “various types of information” may include tool information of machines 20, 22, and 24, load torques and temperatures of servo motors in machines 20, 22, and 24, output signals from various sensors in machines 20, 22, and 24, and the like.

[0083] Such an example is given below in relation to Fig. 4. Section (a) in Fig. 4 shows a timing diagram in which scheduled communication is performed to acquire information from the machine 20.

[0084] The CPU 52 regularly performs the scheduled communication of the machine monitoring signals 100, 102 and 104 for acquiring information of the machine 20 between the CPU 52 and the machine 20 over periods from a time t 31 up to a time t 32 , from a time t 33 up to a time t 34 and from a time t 35 up to a time t 36 through.

[0085] The following is with regard to section (b) in Fig. 4 a function for detecting unauthorized communication when performing the functions described in section (a) in Fig. 4 described communication. In section (b) in Fig. 4, an unauthorized communication 106 is initiated due to unauthorized access to the communication section 58 via the communication network 16 in a period from time t 34 until time t 35in which no communication is planned.

[0086] The CPU 52 constantly monitors the current communication traffic C a in the communication section 58 and compares the current communication traffic C a in communication section 58 with the planned communication traffic C p the planned communication for each given period.

[0087] For example, CPU 52 calculates the current communication traffic C a in communication section 58 in a period T D from a time t p (that is, the time t 31 , t 33 or t 35 ) to start a planned communication P p (i.e. the communication of the signal 100, 102 or 104) until a time t p+1 to the start of the next scheduled communication P p+1 (that is T D = t p+1 - t p ).

[0088] In particular, the CPU 52 sends a command to the timer 60 at each of the times t 31 , t 33 and t 35 to the beginning of the scheduled communication of signals 100, 102, and 104 to begin clocking an elapsed time thereof. Subsequently, CPU 52 calculates the current communication traffic C a in a period until a given time τ6 from each time t 31 , t 33 , t 35 has expired.

[0089] In this regard, the period T D be predicted, since the CPU 52 implements the algorithm described in section (a) in Fig. 4 according to a predetermined program. The predetermined time τ6 is defined as a time interval corresponding to the predicted period T D matching time (i.e. τ6 = T D ) and stored in system memory 54.

[0090] Furthermore, the planned communication traffic C pThe planned communication of signals 100, 102, and 104 can be predicted from, for example, a data format and program of the planned communication. The planned communication traffic C p is also stored in advance in the system memory 54.

[0091] The CPU 52 compares the current communication traffic C a in a period until the time τ6 from time t 31 , t 33 or t 35 has elapsed, with the planned communication traffic C p of the planned communication carried out during this period and determines whether the current communication traffic C a is more than the planned communication traffic C p .

[0092] For example, in section (c) in Fig. 4 example, the CPU 52 the current communication traffic C a in the period until the time τ6 from time t 33has elapsed (that is, corresponding to the period t 33 - t 35 ). In this case, the current communication traffic is C a a sum of the planned communication traffic C p of the signal 102 and the communication traffic of the unauthorized communication 106.

[0093] Accordingly, the CPU 52 determines that the current communication traffic Ca is more than the planned communication traffic C p , and can thus detect that the unauthorized communication 106 in the period t 33 - t 35 has taken place.

[0094] When the unauthorized communication 106 is detected, the CPU 52 serves as a communication blocking section 66 to block communication between the communication section 58 and the communication network 16 over which the unauthorized communication 106 occurred.

[0095] Similarly, the CPU 52 performs scheduled communication of machine monitoring signals for detecting information of the machines 22 and 24 between the CPU 52 and the machines 22 and 24, and can detect unauthorized communication while performing the scheduled communication in the same manner as described above.

[0096] Below is another example of capturing unauthorized communication related to Fig. 5. In this example, the CPU 52 performs the scheduled communication of a machine monitoring signal 110a for acquiring information of the machine 20 between the CPU 52 and the machine 20 as described in section (a) in Fig. 5 represented by.

[0097] Subsequently, the CPU 52 performs the scheduled communication of a machine monitoring signal 112a for acquiring information of the machine 22 between the CPU 52 and the machine 22. Subsequently, the CPU 52 performs the scheduled communication of a machine monitoring signal 114a for acquiring information of the machine 24 between the CPU 52 and the machine 24.

[0098] Thereafter, the CPU 52 performs the scheduled communication in the order of the machine monitor signal 110b for acquiring information of the machine 20, the machine monitor signal 112b for acquiring information of the machine 22, and the machine monitor signal 114b for acquiring information of the machine 24.

[0099] Thus, in this example, CPU 52 performs a series of scheduled communications with respect to the machine monitoring signals in the order of machines 20, 22, and 24.

[0100] Due to the structure of the communication network 16 or the communication system used for communication by the machines 20, 22 and 24, etc., there may be a difference in the communication speed between the cell control device 50 and the machines 20, 22 and 24.

[0101] In such a case, when the signals are transmitted at the respective maximum communication speeds, the communication traffic C of the machine monitoring signals 110a and 110b, the communication traffic C of the machine monitoring signals 112a and 112b and the communication traffic C of the machine monitoring signals 114a and 114b differ from each other as shown in sections (a) and (b) in Fig. 5 shown.

[0102] The following is with regard to section (b) in Fig. 5 a function for detecting unauthorized communication when performing the functions described in section (a) in Fig. 5 described communication. In section (b) in Fig. In the example shown in Figure 5, an unauthorized communication 116 is performed due to unauthorized access to the communication section 58 via the communication network 16, so that it partially overrides the planned communication of the machine monitoring signal 114a.

[0103] The CPU 52 compares the current communication traffic C a with the planned communication traffic C p for any given period, similar to the previous example of section (b) in Fig. 4.

[0104] For example, CPU 52 calculates the current communication traffic C a in communication section 58 for each period T E from a time t q (for example, a time t 41 ) to start a planned communication P qfor collecting information from the machine 20 (for example, the planned communication of the signal 110a) up to a time t q+1 (for example, a time t 47 ) to the start of the next scheduled communication P q+1 for capturing information from the same machine 20 (for example, the planned communication of the signal 110b).

[0105] In particular, the CPU 52 sends a command to the timer 60 at each of the times t 41 and t 47 to the beginning of the scheduled communication of signals 110a and 110b to begin clocking an elapsed time thereof. Subsequently, CPU 52 calculates the current communication traffic C a in a period until a given time τ7 from each of the times t 41 and t 47 has expired.

[0106] In this regard, the CPU 52 performs the operations described in section (a) in Fig. 5 according to a predetermined program. Accordingly, the preceding period T E predictable. The given time τ7 is defined as a time constant corresponding to the predicted period T E matching time (that is, τ7=T E ) and stored in system memory 54.

[0107] On the other hand, the planned communication traffic C p the planned communication of signals 110a, 112a, 114a, 110b, 112b, and 114b. The predicted planned communication traffic C p is also stored in advance in the system memory 54.

[0108] The CPU 52 compares the current communication traffic C a in the period until the time τ7 from time t 41 , t 47 has elapsed (corresponding to the period t 41 - t 47 ), with the planned communication traffic C pof the planned communication in this period and determines whether the current communication traffic C a is more than the planned communication traffic C p .

[0109] For example, in section (b) in Fig. 5 shown example of the current communication traffic C a in the period until the time τ7 from time t 41 has elapsed, a sum of the planned communication traffic C p signals 110a, 112a and 114a and unauthorized communication traffic 116.

[0110] Accordingly, the CPU 52 determines that the current communication traffic C a is more than the planned communication traffic C p , and can thus detect that the unauthorized communication 116 in the period t 41 - t 47 has taken place.

[0111] When the unauthorized communication 116 is detected, the CPU 52 serves as a communication blocking section 66 to block communication between the communication section 58 and the communication network 16 over which the unauthorized communication 116 occurred.

[0112] As previously expressed, the preceding various examples describe the detection of unauthorized communication that interferes with scheduled communication between the manufacturing cell 12 and the cell control device 50. The technical concept of these various examples can also be applied to the detection of unauthorized communication that interferes with scheduled communication between the production management device 14 and the cell control device 50.

[0113] For example, the cell control device 50 determines whether communication traffic between the communication section 58 and the production management device 14 is detected in a period in which the period specified in section (a) in Fig. 2 (i.e. the communication of signals 70 and 84) is not to be carried out.

[0114] In section (a) in Fig. 2, the period in which the scheduled communication between the communication section 58 and the production management device 14 is not to be carried out is a period from time t1 to time t 12 which is predictable from the cycle times of the machines 20, 22 and 24, the amount of information of the signals (of a total communication traffic) determined by, for example, the data format and the communication speeds of the communication networks 16 and 18, etc.

[0115] If the CPU 52 detects that a communication traffic over the communication network 18 in the communication section 58 within the time period t1 - t 12 occurs in which no communication is scheduled, the CPU 52 determines in real time that the current communication traffic in the communication section 58 exceeds the scheduled communication traffic. This allows unauthorized communication via the communication network 18 to be detected.

[0116] When the unauthorized communication via the communication network 18 is detected, the CPU 52 blocks the communication between the communication section 58 and the communication network 18, while not blocking the communication between the communication section 58 and the communication network 16 in which no unauthorized communication is detected.

[0117] In the examples described above, the CPU 52 can periodically generate an authentication key for use in the communication between the communication section 58 and the production management device 14 and the communication between the communication section 58 and the manufacturing cell 12. This can more effectively prevent unauthorized communication.

[0118] The network system 10 may further comprise a second manufacturing cell having a plurality of machines in addition to the Fig. 1, wherein the second manufacturing cell and the communication section 58 may be connected to each other for communication via a third network.

[0119] In this case, if the unauthorized communication via the communication network 16 as described in section (c) in Fig. 2, the CPU 52 blocks communication between the communication section 58 and the communication network 16, while not blocking communication between the communication section 58 and the third communication network. This can cause the second manufacturing cell to continuously perform its work.

[0120] Furthermore, the Fig. 1, the manufacturing cell 12 comprises a total of three machines 20, 22 and 24. However, the manufacturing cell 12 may also comprise one, two or four or more machines.

[0121] Furthermore, in the Fig. In the embodiment illustrated in Figure 1, the communication section 58 may include a first communication section configured to communicate with the production management device 14 and a second communication section configured to communicate with the manufacturing cell 12. In this case, if unauthorized communication is detected in the second communication section, the CPU 52 blocks communication in the second communication section while maintaining communication in the first communication section in which no unauthorized communication is detected.

[0122] Furthermore, in the embodiment described above, the communication network 16 consists of an intranet or LAN and the communication network 18 consists of the Internet or the like.

[0123] However, the communication network 16 or 18 may also consist of a single communication cable that connects the communication section 58 directly to the manufacturing cell 12 or connects the communication section 58 directly to the production management device 14.

[0124] Furthermore, if unauthorized communication is detected in the communication section 58, the CPU 52 can generate an alarm signal indicating this in the form of a sound or image to issue a warning signal to a user. In this case, the cell control device 50 can further include a speaker or a display device through which the cell control device 50 can issue the warning signal.

[0125] Furthermore, in relation to section (b) in Fig. 4 or Fig. 5 described methods for detecting unauthorized communications also apply to detecting unauthorized communications 86, 88 or 98 in paragraph (c) or (d) in Fig. 2 or section (b) in Fig. 3 applicable.

[0126] Furthermore, in relation to paragraph (c) or (d) in Fig. 2 or section (b) in Fig. 3 described method for detecting unauthorized communication also applies to detecting unauthorized communication 106 or 116 in section (b) in Fig. 4 or Fig. 5 applicable.

Claims

[1] A cell control device (50) adapted to control a manufacturing cell (12) comprising a plurality of machines (20, 22, 24) according to a command from a production management device (14), the cell control device comprising: a communication section (58) configured to communicate with the production management device and the manufacturing cell comprising the plurality of machines, wherein the communication section (58) comprises a first communication section configured to communicate with the production management device (14) and a second communication section configured to communicate with the manufacturing cell (12); a communication controller (62) configured to cause the communication section to perform scheduled communication intended to be performed with the production management device or the plurality of machines; a communication detection section (64) configured to monitor a current communication traffic in the communication section, to compare the current communication traffic performed in a monitoring period with the planned communication traffic of the planned communication scheduled to be performed in the monitoring period, to determine whether the current communication traffic is more than the planned communication traffic, and, if the current communication traffic is more than the planned communication traffic, to detect an unauthorized communication (86, 88, 98, 106, 116); and a communication blocking section (66) configured to block communication in that of the first and second communication sections in which unauthorized communication is detected, to maintain communication in that of the first and second communication sections in which no unauthorized communication is detected, wherein the monitoring period is set to be a period from a start time of a first scheduled communication to a start time of a second scheduled communication executed after the first scheduled communication, and wherein, within the monitoring period, periods in which no communication is planned are predicted by cycle times of work performed by the plurality of machines. [2] The cell control device according to claim 1, wherein the communication controller is arranged to cause the communication section to perform the second scheduled communication subsequent to the first scheduled communication. [3] The cell control device according to claim 1, wherein the communication controller causes the communication section to: to perform the first scheduled communication and the second scheduled communication with one of the production management device and the plurality of machines; and perform a third scheduled communication with the other of the production management device and the plurality of machines between the first scheduled communication and the second scheduled communication. [4] A cell control device adapted to control a manufacturing cell (12) comprising a plurality of machines (20, 22, 24) according to a command from a production management device (14), the cell control device comprising: a communication section (58) configured to communicate with the production management device and the manufacturing cell comprising the plurality of machines, wherein the communication section (58) comprises a first communication section configured to communicate with the production management device (14) and a second communication section configured to communicate with the manufacturing cell (12); a communication controller (62) configured to cause the communication section to perform scheduled communication scheduled to be performed with the production management device or the plurality of machines; a communication detection section (64) configured to monitor a current communication traffic in the communication section, to compare the current communication traffic performed in a monitoring period with the planned communication traffic of the planned communication scheduled to be performed in the monitoring period, to determine whether the current communication traffic is more than the planned communication traffic, and, if the current communication traffic is more than the planned communication traffic, to detect an unauthorized communication (86, 88, 98, 106, 116); and a communication blocking section (66) configured to block communication in that of the first and second communication sections in which unauthorized communication is detected, to maintain communication in that of the first and second communication sections in which no unauthorized communication is detected, wherein the monitoring period is set to be a period from an end time of a first scheduled communication to a start time of a second scheduled communication executed after the first scheduled communication, wherein, within the monitoring period, periods in which no communication is planned are predicted by cycle times of work performed by the plurality of machines, wherein the communication controller is arranged to cause the communication section to carry out the second scheduled communication subsequent to the first scheduled communication, wherein the communication detecting section is configured to detect in real time that the current communication traffic is more than the scheduled communication traffic when the current communication traffic is detected in the monitoring period.

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