Wireless communication system

Abstract

A wireless communication system according to the present invention comprises: a plurality of transmission devices; and a plurality of reception devices that can perform wireless communication compliant with safety standards with the plurality of transmission devices. Upon receipt of a stop command provided by a user, each of the plurality of transmission devices transmits, to the plurality of reception devices via the wireless communication, stop information for stopping an apparatus connected to each of the plurality of reception devices. Each of the plurality of reception devices stops an apparatus connected thereto on the basis of the reception of the stop information.

Description

Wireless communication system

[0001] This disclosure relates to a wireless communication system.

[0002] Japanese Patent Application Laid-Open No. 2022-66556 describes a technique for easily configuring a system for wirelessly operating a device.

[0003] By the way, when a device such as a robot and a human user work in the same space, the user may be required to carry a device for safely stopping the device. At this time, in the prior art as disclosed in Japanese Patent Application Laid-Open No. 2022-66556, a plurality of users cannot safely stop a plurality of devices that perform operations in the same space, and there is room for improvement.

[0004] Therefore, an object of the present disclosure is to provide a wireless communication system that enables each user carrying a transmission device to work in the same space as a plurality of devices connected to each reception device capable of wireless communication with the transmission device.

[0005] To achieve the above object, the wireless communication system according to the present disclosure includes a plurality of transmission devices and a plurality of reception devices capable of wireless communication compliant with the safety standards of the plurality of transmission devices. Each transmission device of the plurality of transmission devices transmits, by the wireless communication, stop information for stopping the devices connected to each reception device of the plurality of reception devices to the plurality of reception devices based on receiving a stop instruction from a user. Each reception device stops the device connected to itself based on receiving the stop information.

[0006] According to the present disclosure, it is possible to provide a wireless communication system that enables each user carrying a transmission device to work in the same space as a plurality of devices connected to each reception device capable of wireless communication with the transmission device.

[0007] This is a diagram illustrating an example of the schematic configuration of a wireless communication system. This is a flowchart showing the flow of the stop process. This is the first explanatory diagram illustrating the operation sequence of the stop process. This is the second explanatory diagram illustrating the operation sequence of the stop process. This is the third explanatory diagram illustrating the operation sequence of the stop process. This is a flowchart showing the flow of the join process. This is a flowchart showing the flow of the join decision process. This is the first explanatory diagram illustrating the operation sequence of the join process and the join decision process. This is the second explanatory diagram illustrating the operation sequence of the join process and the join decision process. This is the third explanatory diagram illustrating the operation sequence of the join process and the join decision process. This is a flowchart showing the flow of the leave process. This is a flowchart showing the flow of the leave decision process. This is the first explanatory diagram illustrating the operation sequence of the leave process and the leave decision process. This is the second explanatory diagram illustrating the operation sequence of the leave process and the leave decision process. This is an explanatory diagram illustrating an example of a wireless communication system protocol. This is a flowchart showing the flow of the secure communication establishment process. This is a flowchart showing the flow of the response process. This is the first explanatory diagram illustrating the operation sequence of the secure communication establishment process and the response process. This is the second explanatory diagram illustrating the operation sequence of the secure communication establishment process and the response process.

[0008] The wireless communication system 10 according to this embodiment will be described below. (First Embodiment) First, the first embodiment of the wireless communication system 10 according to this embodiment will be described. Figure 1 is a diagram showing an example of the schematic configuration of the wireless communication system 10.

[0009] As shown in Figure 1, the wireless communication system 10 includes a stop device 20 and a robot stop device 30. The stop device 20 and the robot stop device 30 are capable of external communication via wireless communication. Although only one stop device 20 and one robot stop device 30 are shown in Figure 1, the wireless communication system 10 includes multiple stop devices 20 (e.g., stop devices 20A, 20B, 20C, etc.) and multiple robot stop devices 30 (e.g., robot stop devices 30A, 30B, 30C, etc.) not shown. The stop device 20 is an example of a "transmitting device" in this disclosure, and the robot stop device 30 is an example of a "receiving device" in this disclosure.

[0010] The stopping device 20 comprises a control unit 21, a control unit 22, a storage unit 23, a storage unit 24, a communication unit 25, and an operation unit 26.

[0011] Control unit 21 and control unit 22 are each composed of different CPUs (Central Processing Units) and other circuits, and perform functions such as generating stop information, transmitting stop information to the communication unit 25, and receiving stop information from the communication unit 25, as described later. Control unit 21 is an example of the "first processor" of this disclosure, and control unit 22 is an example of the "second processor" of this disclosure.

[0012] The memory units 23 and 24 store various information necessary for performing wireless communication (hereinafter referred to as "safety communication") between the stop device 20 and the robot stop device 30 in accordance with safety standards. For example, the safety communication is performed using the communication method specified in IEC 61784-3 (Black Channel Communication Protocol). However, the communication method for safety communication is not limited to IEC 61784-3, and known standards can be used as appropriate. The various information includes, for example, member information indicating a member list of a group consisting of one or more stop devices 20 and one or more robot stop devices 30 capable of safety communication with the one or more stop devices 20, and programs for executing various processes described later. The various information stored in the memory unit 23 is used by the control unit 21 for processing, and the various information stored in the memory unit 24 is used by the control unit 22 for processing.

[0013] The communication unit 25 transmits and receives information using a communication protocol that enables communication between multiple devices. The communication unit 25 does not modify or change the information.

[0014] The operation unit 26 consists of various switches that can be operated by the user. The on / off states of the various switches constituting the operation unit 26 are monitored by the control unit 21 and the control unit 22. The various switches constituting the operation unit 26 may consist of either hardware switches or software switches.

[0015] The robot stopping device 30 comprises a control unit 31, a control unit 32, a storage unit 33, a storage unit 34, a communication unit 35, and a power cut-off relay 36. The robot stopping device 30 may also include other components in place of the power cut-off relay 36, as long as they are capable of providing a safety output.

[0016] Control unit 31 and control unit 32 are each composed of different CPUs and other circuits, and receive stop information from the communication unit 35 and confirm the contents of the stop information. Control unit 31 is an example of the "third processor" of this disclosure, and control unit 32 is an example of the "fourth processor" of this disclosure.

[0017] The memory units 33 and 34 store various information necessary for safe communication between the stop device 20 and the robot stop device 30. This information is the same as the information stored in memory units 23 and 24. The information stored in memory unit 33 is used by the control unit 31 for processing, and the information stored in memory unit 34 is used by the control unit 32 for processing.

[0018] The communication unit 35 transmits and receives information using a communication protocol that enables communication between multiple devices. The communication unit 35 does not modify or change the information.

[0019] Control units 31 and 32 acquire a stop request from the received stop information, output a state corresponding to the stop request (e.g., STO (Safe Torque Off)), and stop the robot connected to the robot stop device 30. Here, "stop" includes the concepts of emergency stop performed in the event of an emergency and other stops. Examples of robots include service robots, industrial robots, and agricultural robots. A robot is an example of the "equipment" in this disclosure.

[0020] Here, the control units 21 and 22 of the stop device 20 receive a stop command from the user, for example, when the stop switch, which is one of the various switches on the operation unit 26, is operated, and each generates the stop information described above. The generated stop information is confirmed by the control units 21 and 22, respectively, to ensure its correctness. In this way, the control units 21 and 22 confirm the stop information they have generated, then authorize the transmission of the stop information, and transmit the stop information to the communication unit 25.

[0021] The communication unit 25 transmits the received stop information to all other devices in the group indicated in the member information stored in the storage units 23 and 24 without editing it.

[0022] The communication unit 35 of the robot stop device 30 receives stop information from the stop device 20 and transmits it to the control unit 31 and the control unit 32. The control unit 31 and the control unit 32 each verify the validity of the content of the received stop information. The correctness of the received stop information is guaranteed by the verification by the control unit 31 and the control unit 32. After confirming the stop information received by each other, the control unit 31 and the control unit 32 control the power cutoff relay 36 according to the safety state indicated in the stop information in order to stop the robot connected to the robot stop device 30. "Safe state" refers to a state such as STO as defined in IEC 60204. As a result, the robot stop device 30 transitions to a safe state and the robot connected to the robot stop device 30 stops. The communication unit 35 transmits a response to the stop device 20 that transmitted the stop information, indicating that the state of the robot stop device 30 has transitioned to a safe state.

[0023] The communication unit 25 of the stopping device 20 receives a response from the robot stopping device 30 and transmits it to the control unit 21 and the control unit 22. Based on this response, the control unit 21 and the control unit 22 confirm that the robot connected to the robot stopping device 30 has stopped.

[0024] As described above, in the wireless communication system 10, the control units 21 and 22 of the stop device 20 confirm the stop information generated by each other and then permit the transmission of stop information to the multiple robot stop devices 30. In this embodiment, whether the stop information generated by each device matches or does not match as a result of the mutual check, the transmission of stop information to the multiple robot stop devices 30 is permitted. Then, the control units 31 and 32 of the robot stop device 30 confirm the stop information received by each device and then stop the robot connected to their own device. In this embodiment, whether the content of the stop information confirmed by each device matches or does not match as a result of the mutual check, the robot connected to their own device is stopped. Thus, with the wireless communication system 10, by making the safety hardware of the stop device 20 and the robot stop device 30 redundant, safe communication between the stop device 20 and the robot stop device 30 can be ensured.

[0025] Figure 2 is a flowchart showing the flow of the stop process performed by each device within the group. Each of the stop devices 20 and robot stop device 30, which can be these devices, performs the stop process using the hardware resources shown in Figure 1. As an example, the stop process is repeatedly performed at regular intervals.

[0026] In the following, the stopping process will be explained for each device within the above group, in the following order: a stopping device 20 in which the user operates the stop switch, which is one of the various switches on the operation unit 26; a stopping device 20 in which the stop switch is not operated; and a robot stopping device 30. In the following explanation of the stopping process, a stopping device 20 in which the user operates the stop switch will be referred to as a "stopping device (master)," and a stopping device 20 in which the stop switch is not operated will be referred to as a "stopping device (slave)."

[0027] <Stopping Device (Master)> In step S10 shown in Figure 2, the stopping device (master) checks the status of its own device. Here, since the user has operated the stop switch, the stopping device (master) determines that the stop command is ON. Then, the process proceeds to step S11.

[0028] In step S11, the stopping device (master) confirms the validity of the group from the safety communication. Then, the process proceeds to step S12.

[0029] In step S12, the stop device (master) determines whether the group is valid or not. Assuming the group is valid, the process proceeds to step S13.

[0030] In step S13, the stop device (master) sends predetermined communications to all other devices in the group via secure communication. The stop device (master) also receives predetermined communications from all other devices in the group via secure communication. Then, the process proceeds to step S14.

[0031] In step S14, the stop device (master) determines whether or not to transition to a safe state. For example, if the robot stop device 30 is the main entity in the stop process, it is determined that the system will transition to a safe state. In this case, since the stop device (master) is the main entity in the stop process, the process ends.

[0032] <Stop device (slave)> In step S10, the stop device (slave) checks the status of its own device. Here, no operation is performed on the stop device (slave), so the status of the stop device (slave) has not changed. In other words, the stop device (slave) determines that the stop command is turned off. Then, the process proceeds to step S11.

[0033] In step S11, the stop device (slave) confirms the validity of the group from the safety communication. Then, the process proceeds to step S12.

[0034] In step S12, the stop device (slave) determines whether the group is valid or not. Assuming the group is valid, the process proceeds to step S13.

[0035] In step S13, the stop device (slave) communicates predetermined information to all other devices in the group via secure communication. The stop device (slave) also receives predetermined information from all other devices in the group via secure communication. Here, the stop device (slave) confirms that stop information has been transmitted from the stop device (master) via predetermined communication. Then, the process proceeds to step S14.

[0036] In step S14, the stop device (slave) determines whether or not to transition to a safe state. Here, since the stop device (slave) is the main entity responsible for the stop process, the process ends.

[0037] <Robot Stop Device 30> In step S10, the robot stop device 30 checks the status of its own device. Here, no operation is performed on the robot stop device 30, so the status of the robot stop device 30 has not changed. Then, the process proceeds to step S11.

[0038] In step S11, the robot stop device 30 confirms the validity of the group from the safety communication. Then, the process proceeds to step S12.

[0039] In step S12, the robot stopping device 30 determines whether the group is valid or not. Assuming the group is valid, the process proceeds to step S13.

[0040] In step S13, the robot stop device 30 transmits predetermined communications to all other devices in the group via safety communication. The robot stop device 30 also receives predetermined communications from all other devices in the group via safety communication. Here, the robot stop device 30 confirms that stop information has been transmitted from the stop device (master) via predetermined communication. Then, the process proceeds to step S14.

[0041] In step S14, the robot stop device 30 determines whether or not to transition to a safe state. Here, the robot stop device 30 is the main entity responsible for the stop process, and since the robot stop device 30 received stop information in step S13, the process proceeds to step S15.

[0042] In step S15, the robot stop device 30 transitions itself to a safe state. As a result, the robot connected to the robot stop device 30 stops. Then, the process proceeds to step S16.

[0043] In step S16, the robot stop device 30 notifies other devices within the group via secure communication that it has transitioned to the safe state. Then, the process ends.

[0044] As described above, in the wireless communication system 10, each stop device 20 transmits, via secure communication, stop information for stopping the robots connected to each robot stop device 30 to a plurality of robot stop devices 30 based on receiving a stop instruction from the user. Then, each robot stop device 30 stops the robot connected to itself based on receiving the stop information. As a result, according to this wireless communication system 10, each user carrying the stop device 20 can work in the same space as the plurality of robots connected to each robot stop device 30 capable of secure communication with the stop device 20. Also, according to this wireless communication system 10, since the plurality of robots connected to each robot stop device 30 stop simultaneously, the minimum separation distance between the user and the robots in the work space described in ISO 13855 can be shortened. Also, according to this wireless communication system 10, since it is not necessary to select the robot to be stopped in the stop device 20, a mechanism for selecting the robot to be stopped is not required and the stop device 20 can be lightweight. Also, according to this wireless communication system 10, due to the secure communication compliant with the black channel of IEC 61784-3, it is possible to safely stop even the mobile robot.

[0045] Next, the operation sequence of the stop process will be described using FIGS. 3 to 5. As an example, in this operation sequence, as one or more stop devices 20 constituting a predetermined group, a stop device (master) and a stop device (slave) appear, and as one or more robot stop devices 30 constituting a predetermined group, a robot stop device A and a robot stop device B appear.

[0046] As shown in FIG. 3, the stop device (master) transmits stop information to all other devices in the group based on the operation of the stop switch by the user.

[0047] As shown in FIG. 4, the robot stop device A and the robot stop device B confirm the validity of the content of the received stop information, and transition their own devices to a safe state when it is valid. Note that the stop device (slave) maintains its original state without transitioning to a safe state.

[0048] As shown in FIG. 5, the robot stop device A and the robot stop device B transmit at least a response indicating that they have transitioned to a safe state to the stop device (master). Note that the stop device (slave) may also transmit a response indicating the state of its own device to the stop device (master), similar to the robot stop device A and the robot stop device B.

[0049] According to the above operation sequence, the wireless communication system 10 can safely stop all robots connected to the robot stop device A and the robot stop device B.

[0050] FIG. 6 is a flowchart showing the flow of participation processing executed by a predetermined stop device 20 or a predetermined robot stop device 30 that wishes to participate in a group. The stop device 20 and the robot stop device 30 each execute the participation processing using the hardware resources shown in FIG. 1. As an example, the participation processing is executed when a predetermined input operation is performed on the stop device 20 or the robot stop device 30 by the user. For example, in the stop device 20, when the participation switch, which is various switches of the operation unit 26, is operated as the predetermined input operation, the participation processing is executed. Note that the robot stop device 30 may also be provided with a participation switch similar to the above. Hereinafter, the flow of the participation processing will be described taking the stop device 20 as an example.

[0051] In step S20 shown in FIG. 6, the stop device 20 eavesdrops on the communication of the surrounding groups and searches for groups that can be participated in. Then, the process proceeds to step S21.

[0052] In step S21, the stopping device 20 selects the group that wishes to participate. For example, if multiple groups are found in step S20, the stopping device 20 selects the group that is closest to the stopping device 20 as the group that wishes to participate. Then, the process proceeds to step S22.

[0053] In step S22, the stop device 20 sends a participation request via secure communication to all other devices in the group that wish to participate. Then, the process proceeds to step S23.

[0054] In step S23, the stop device 20 determines whether there has been no response within a predetermined time since sending the join request, i.e., whether a timeout has occurred. If the stop device 20 determines that a timeout has occurred (step S23: YES), it proceeds to step S24. On the other hand, if the stop device 20 determines that a timeout has not occurred (step S23: NO), it proceeds to step S25. Note that step S23 is not limited to determining whether a timeout has occurred. As another example, in step S23, it may be determined whether or not an termination request has been received from an external source. For example, the stop device 20 may be equipped with a termination button as one of the various switches on the operation unit 26, and when the termination button is operated, it may proceed to step S24. Alternatively, in step S23, if a join rejection response (a response rejecting a join request) is received from the slave device, it may proceed to step S24.

[0055] In step S24, the stop device 20 updates the state of its own device. Here, since the stop device 20 is the main entity in the participating process, the stop device 20 maintains its current state. On the other hand, if the robot stop device 30 is the main entity in the participating process, the robot stop device 30 transitions its own device to a safe state in step S24. Then the process ends.

[0056] In step S25, the stop device 20 determines whether it has received permission to participate from all other devices in the group it wishes to join. If the stop device 20 determines that it has received permission to participate from all other devices (step S25: YES), it proceeds to step S26. On the other hand, if the stop device 20 determines that it has not received permission to participate from all other devices (step S25: NO), it returns to step S23.

[0057] In step S26, the stopping device 20 updates the group member information. Specifically, the stopping device 20 adds its own device to the group member list and stores the member information in the storage unit 23 and storage unit 24, respectively. Then the process ends.

[0058] As explained above, in the participation process, the device that sent the participation request joins the group when it determines that secure communication has been established by receiving permission to participate from all other devices in the group that wish to participate. In addition, if permission to participate is not received from all other devices in the participation process, the device that sent the participation request, specifically the robot stop device 30, transitions itself to a safe state.

[0059] Figure 7 is a flowchart showing the flow of the participation decision process executed by all other devices in the group that received the participation request in step S22. The stop device 20 and the robot stop device 30, which may be such other devices, each execute the participation decision process using the hardware resources shown in Figure 1. As an example, the participation decision process is executed when a participation request is received. Below, the flow of the participation decision process will be explained using the robot stop device 30 as an example.

[0060] In step S30 shown in Figure 7, the robot stop device 30 determines whether the device that sent the participation request (e.g., stop device 20) can join the group. If the robot stop device 30 determines that the device can join the group (step S30: YES), it proceeds to step S31. On the other hand, if the robot stop device 30 determines that the device cannot join the group (step S30: NO), it terminates the process. As an example, the robot stop device 30 determines that the device that sent the participation request can join the group if it is not present in the member list shown in the member information of the group stored in the storage unit 33 and the storage unit 34, respectively. On the other hand, the robot stop device 30 determines that the device that sent the participation request cannot join the group if it is present in the member list.

[0061] In step S31, the robot stopping device 30 updates the group member information. Specifically, the robot stopping device 30 adds the device that sent the participation request to the member list. Then, the process proceeds to step S32.

[0062] In step S32, the robot stopping device 30 returns permission to participate to the device that sent the participation request. Then the process ends.

[0063] As described above, in the wireless communication system 10, a stop device 20 or robot stop device 30 that wishes to join a group transmits a request to join to one or more stop devices 20 and one or more robot stop devices 30 that constitute the group. Then, based on receiving permission to join from one or more stop devices 20 and one or more robot stop devices 30 that received the request to join, the stop device 20 or robot stop device 30 that wishes to join the group joins the group and secure communication between the devices in the group is permitted. Thus, according to the wireless communication system 10, a device that wishes to join a group can join the group without stopping any of the devices in the group.

[0064] Next, the operation sequences of the participation process and the participation decision process will be explained using Figures 8 to 10. As shown in Figure 8, the stop device 20 that wishes to join a group intercepts communications of surrounding groups and searches for a group it can join. Here, the stop device 20 extracts two groups, Group 1 and Group 2, and grasps the list of members for each group (e.g., Group 1 → Member 1: Stop device 20, Member 2: Robot stop device 30, Member 3: Robot stop device 30; Group 2 → Member 1: Stop device 20, Member 2: Robot stop device 30, Member 3: Robot stop device 30). The stop device 20 then selects Group 1, which is the closest to itself, as the group it wishes to join, and sends a participation request to all other devices in Group 1.

[0065] As shown in Figure 9, all other devices within Group 1 (e.g., Members 1-3) each perform the participation decision process shown in Figure 7 and return permission to participate to the stop device 20 that wishes to join Group 1.

[0066] As shown in Figure 10, the stop device 20 joins group 1 as member 4, and secure communication between devices in group 1 is permitted. In this case, when the user operates the stop switch of the stop device 20, only the robots connected to the robot stop device 30 in group 1 will stop, and the other robots will continue to operate. By automating the grouping in this way, the user can always safely stop only robots that meet specific conditions (e.g., robots close to the stop device 20) without being aware of the groups.

[0067] Figure 11 is a flowchart showing the flow of the departure process performed by a predetermined stop device 20 or a predetermined robot stop device 30 that wishes to leave the group. The stop device 20 and the robot stop device 30 each perform the departure process using the hardware resources shown in Figure 1. As an example, the departure process is performed when a predetermined input operation is performed by the user to the stop device 20 or the robot stop device 30. For example, in the stop device 20, the departure process is performed when the departure switch, which is one of the various switches on the operation unit 26, is operated as the predetermined input operation. The robot stop device 30 may also be provided with a departure switch similar to the one described above. Below, the flow of the departure process will be explained using a stop device 20 that has joined group 1 as member 4 as an example.

[0068] In step S40 shown in Figure 11, the stop device 20 sends a withdrawal request to all other devices in group 1 via safety communication. Then, the process proceeds to step S41.

[0069] In step S41, the stop device 20 determines whether there has been no response within a predetermined time since sending the release request, i.e., whether a timeout has occurred. If the stop device 20 determines that a timeout has occurred (step S41: YES), it proceeds to step S42. On the other hand, if the stop device 20 determines that a timeout has not occurred (step S41: NO), it proceeds to step S43.

[0070] In step S42, the stop device 20 updates the state of its own device. Here, since the stop device 20 is the main entity performing the detachment process, the stop device 20 maintains its current state. On the other hand, if the robot stop device 30 is the main entity performing the detachment process, the robot stop device 30 transitions its own device to a safe state in step S42. Then the process ends.

[0071] In step S43, the stop device 20 determines whether or not it has received permission to depart from all other devices in group 1. If the stop device 20 determines that it has received permission to depart from all other devices (step S43: YES), it proceeds to step S44. On the other hand, if the stop device 20 determines that it has not received permission to depart from all other devices (step S43: NO), it returns to step S41.

[0072] In step S44, the stop device 20 updates the member information of group 1. Specifically, the stop device 20 deletes its own device from the member list indicated in the member information of group 1 stored in storage unit 23 and storage unit 24, respectively. Then the process ends.

[0073] As explained above, in the withdrawal process, the device that sent the withdrawal request withdraws from the group after determining that safe communication has been established by receiving withdrawal permission from all other devices within Group 1. In addition, if the device that sent the withdrawal request does not receive withdrawal permission from all other devices in the withdrawal process, the device that sent the withdrawal request, specifically the robot stop device 30, transitions itself to a safe state.

[0074] Figure 12 is a flowchart showing the flow of the departure decision process executed by all other devices in Group 1 that received the departure request in step S40. The stop device 20 and the robot stop device 30, which may be these other devices, each execute the departure decision process using the hardware resources shown in Figure 1. As an example, the departure decision process is executed when a departure request is received. The flow of the departure decision process will be explained below using the robot stop device 30 as an example.

[0075] In step S50 shown in Figure 12, the robot stop device 30 determines whether the device that sent the detachment request (e.g., stop device 20) can detach from group 1. If the robot stop device 30 determines that the device can detach from group 1 (step S50: YES), it proceeds to step S51. On the other hand, if the robot stop device 30 determines that the device cannot detach from group 1 (step S50: NO), it terminates the process. As an example, the robot stop device 30 determines that the device that sent the detachment request can detach from group 1 if it is listed in the member list shown in the member information of group 1 stored in memory unit 33 and memory unit 34, respectively. On the other hand, the robot stop device 30 determines that the device that sent the detachment request cannot detach from group 1 if it is not listed in the member list.

[0076] In step S51, the robot stopping device 30 updates the member information of group 1. Specifically, the robot stopping device 30 removes the device that sent the withdrawal request from the member list. Then, the process proceeds to step S52.

[0077] In step S52, the robot stopping device 30 returns a release permission to the device that sent the release request. Then the process ends.

[0078] As described above, in the wireless communication system 10, a stop device 20 or robot stop device 30 that wishes to leave a group transmits a departure request to one or more stop devices 20 and one or more robot stop devices 30 that constitute the group. Then, based on receiving permission to leave from one or more stop devices 20 and one or more robot stop devices 30 that received the departure request, the stop device 20 or robot stop device 30 that wishes to leave the group leaves the group, and secure communication between devices in the group is prohibited. As a result, according to the wireless communication system 10, a predetermined device can be removed from a group without stopping the devices in the group.

[0079] Next, the operation sequences of the detachment process and the detachment decision process will be explained using Figures 13 to 15. As shown in Figure 13, the stop device 20, which wishes to detach from group 1, sends a detachment request to all other devices in group 1 (e.g., members 1 to 3).

[0080] As shown in Figure 14, all other devices within Group 1 each execute the withdrawal decision process shown in Figure 12 and return a withdrawal permission to the stop device 20 that wishes to withdraw from Group 1.

[0081] As shown in Figure 15, the stop device 20 is separated from group 1, and secure communication between devices in group 1 is prohibited.

[0082] Figure 16 is an explanatory diagram illustrating an example protocol of the wireless communication system 10. In Figure 16, there are two masters that transmit stop information: Master 1's stop device 20A and Master 2's stop device 20B. There are also two slaves that receive stop information: Slave 1's robot stop device 30A and Slave 2's robot stop device 30B. One of the stop devices 20A and 20B becomes Slave 3 when receiving stop information from the other. Here, stop device 20A first transmits stop information 40 to slaves 1-3, and then stop device 20B transmits stop information 50 to slaves 1-3.

[0083] As described above, the wireless communication system 10 uses a communication protocol compliant with IEC 61784-3 to perform secure communication. Furthermore, the wireless communication system 10 applies Sequence number (corresponding to SN described later), Connection authentication (corresponding to ID described later), Data integrity assurance (corresponding to CRC described later), and Time expectation (corresponding to WD described later) as error countermeasures for communication errors defined in IEC 61784-3. The wireless communication system 10 then uses the concept of CANopen Safety to realize many-to-many secure communication between multiple stop devices 20 and multiple robot stop devices 30. Specifically, in the wireless communication system 10, secure communication is achieved by performing the above error countermeasures on both the transmitting and receiving sides and checking the validity of the data, thereby realizing secure data exchange.

[0084] First, the stopping device 20A generates stopping information 40 and transmits the generated stopping information 40 to the stopping device 20B, the robot stopping device 30A, and the robot stopping device 30B.

[0085] The stop information 40 is 16-bit information consisting of SN (sequence number), ID (transmission ID), DATA (safety data), and CRC (cyclic redundancy check).

[0086] The signal-to-noise ratio (SN) is 1 bit and alternates between "0" and "1" to indicate that the same data is not being transmitted consecutively.

[0087] The ID is 5 bits long, with bit 0 representing Master 1, bit 1 representing Master 2, bit 2 representing Slave 1, bit 3 representing Slave 2, and bit 4 representing the Master number.

[0088] The DATA is 2 bits long, with the stop request indicated by the 0th bit and the response by the 1st bit. The CRC is an 8-bit CRC-8.

[0089] Next, the stop device 20B, the robot stop device 30A, and the robot stop device 30B, which have received the stop information 40, return responses 42, 44, and 46 to the stop device 20A, respectively. Responses 42, 44, and 46 are 16-bit pieces of information, similar to the stop information 40, and include SN, ID, DATA, and CRC.

[0090] The stop device 20A has a WD (Watch Dog) function that monitors the period from the transmission of stop information 40 until the reception of responses 42, 44, and 46, respectively.

[0091] After the stop device 20A has finished transmitting the stop information 40, the stop device 20B generates stop information 50 and transmits the generated stop information 50 to the stop device 20A, the robot stop device 30A, and the robot stop device 30B.

[0092] The stop information 50 is 16-bit information consisting of SN, ID, DATA, and CRC, similar to the stop information 40 described above.

[0093] Next, the stop device 20A, robot stop device 30A, and robot stop device 30B, which have received the stop information 50, return responses 52, 54, and 56 to the stop device 20B, respectively. Responses 52, 54, and 56 are 16-bit pieces of information, similar to the stop information 40, and include SN, ID, DATA, and CRC.

[0094] The stop device 20B has a WD function that monitors the period from the transmission of stop information 50 until the reception of responses 52, 54, and 56, respectively.

[0095] As described above, the stopping devices 20A and 20B generate information that can identify the multiple stopping devices 20 and the multiple robot stopping devices 30, specifically, stopping information 40 and 50 that includes the above-mentioned ID. This makes it easier for the wireless communication system 10 to detect communication errors such as "resequencing" and "delay" as defined in IEC 61784-3.

[0096] Furthermore, the stop devices 20A and 20B transmit stop information 40 and 50 to other stop devices 20 and to a plurality of robot stop devices 30. Upon receiving the stop information 40 and 50, each robot stop device 30 of the stop device 20 and the plurality of robot stop devices 30 returns a response indicating the status of its own device (e.g., response 42, response 44, response 46, response 52, response 54, and response 56) to the stop device 20A or 20B that transmitted the stop information 40 and 50. As a result, the wireless communication system 10 can detect communication errors such as "Masquerade" and "Addressing" as defined in IEC 61784-3.

[0097] Next, we will explain how to manage the member lists shown in the member information stored in the stopping device 20 and the robot stopping device 30, respectively.

[0098] As a prerequisite, the member list is updated only when a device joins or leaves a group. Furthermore, groups are formed by combinations of IDs of the broadcasting devices. And, by default, communications within a group are sent to all group members.

[0099] If a member list exists, for example, when the robot stop device 30 is powered on, it reads the member list shown in the member information stored in the memory unit 33 and memory unit 34, respectively. After that, it sets a communication waiting period for a certain time and waits until communication is established with all other devices in the group. If no communication is received from any other devices in the group after the certain period has elapsed, the robot stop device 30 sends a status update notification to all other devices in the group. If there is no response from any of the other devices in the group to the status update notification, the robot stop device 30 transitions itself to a safe state. On the other hand, if the robot stop device 30 receives a response to the status update notification from another device in the group, it checks whether the ID of the device included in the response matches the information in the member list. If the IDs do not match, the robot stop device 30 transitions itself to a safe state and returns the status of its own device to the device that sent the response.

[0100] Furthermore, if the stop device 20 performs the above processing, the current state will be maintained without transitioning to a safe state.

[0101] On the other hand, if a member list does not exist, for example, the stop device 20, as described above, creates a member list that includes its own device when it executes the participation process, and stores the member information including the member list in the storage unit 23 and the storage unit 24, respectively.

[0102] Next, we will explain how to determine whether the above member list is valid or not. The prerequisites are the same as those for managing the above member list.

[0103] When each device within the group communicates periodically, for example, the robot stop device 30 receives periodic communications from all other devices in the group and checks whether the ID of the device included in the periodic communication matches the information in the member list. If the ID does not match, or if there are no periodic communications from any other devices in the group within a certain period, the robot stop device 30 transitions itself to a safe state. If the above process is performed by the stop device 20, the current state is maintained without transitioning to a safe state.

[0104] On the other hand, if each device within the group does not communicate periodically, for example, the robot stop device 30, upon receiving some kind of communication (e.g., stop information), checks whether the ID of the device included in the communication matches the information in the member list. If the ID does not match, the robot stop device 30 transitions its own device to a safe state. If the above process is performed by the stop device 20, the current state is maintained without transitioning to a safe state.

[0105] (Second Embodiment) Next, a second embodiment of the wireless communication system 10 according to this embodiment will be described, omitting or simplifying parts that overlap with the above embodiment.

[0106] The wireless communication system 10 according to the second embodiment differs from the first embodiment in that it performs a secure communication establishment process before transmitting a request to join a group in order to ensure the reliability of the stop device 20 or robot stop device 30 that transmits the request to join the group. Specifically, the wireless communication system 10 executes a subroutine based on the flowchart shown in Figure 17 between steps S21 and S22 of the joining process shown in Figure 6.

[0107] Figure 17 is a flowchart showing the flow of the secure communication establishment process performed by a predetermined stop device 20 or a predetermined robot stop device 30 that wishes to join the group. The stop device 20 and the robot stop device 30 each perform the secure communication establishment process using the hardware resources shown in Figure 1. The flow of the secure communication establishment process will be explained below using the stop device 20 as an example.

[0108] In step S60 shown in Figure 17, the stop device 20 transitions its state to the initial state (SN: Init). Here, "SN: Init" is specifically set to "SN: 0". Then, the process proceeds to step S61.

[0109] In step S61, the stop device 20 creates a safety communication start command. The safety communication start command is an example of a "request to start wireless communication" as described in this disclosure. Then, the process proceeds to step S62.

[0110] Here, the secure communication start command consists of an ID, SN, DATA, and CRC. The ID includes the identification information of all other devices in the group selected in step S21 shown in Figure 6, and the identification information of the stop device 20. The SN includes a periodic communication number that is set according to the current state of the stop device 20, such as "0: Init / 1, 2, ...". Specifically, "SN: 0" is set in the initial state, and the number increases thereafter as communication progresses. The DATA includes a secure communication start request, which includes the conditions and messages for starting secure communication. The CRC includes an error check code created from the ID, SN, and DATA, and is used to verify the integrity of the communication.

[0111] In step S62, the stop device 20 sends a safety communication start command via safety communication to all other devices in the group that wish to participate. Then, the process proceeds to step S63.

[0112] In step S63, the stop device 20 determines whether there has been no response within a predetermined time since sending the safety communication start command, i.e., whether a timeout has occurred. If the stop device 20 determines that a timeout has occurred (step S63: YES), it terminates the process. On the other hand, if the stop device 20 determines that a timeout has not occurred (step S63: NO), it proceeds to step S64.

[0113] In step S64, the stop device 20 determines whether it has received responses from all other devices in the group that wish to participate. If the stop device 20 determines that it has received responses from all other devices (step S64: YES), it proceeds to step S65. On the other hand, if the stop device 20 determines that it has not received responses from all other devices (step S64: NO), it returns to step S63.

[0114] In step S65, the stop device 20 transitions its state to a periodic communication state. This establishes secure communication between the stop device 20 and all other devices in the group that wish to join. Specifically, the stop device 20 starts periodic communication by changing from "SN:0" to "SN:1". This establishes reliable communication among all devices in the group, and prepares them to join the group. After that, the process returns to the main routine and proceeds to step S22 shown in Figure 6.

[0115] Figure 18 is a flowchart showing the flow of response processing performed by all other devices in the group to which the safety communication start command was sent in step S62. The stop device 20 and the robot stop device 30, which may be such other devices, each perform response processing using the hardware resources shown in Figure 1. As an example, response processing is performed when the safety communication start command is received. The flow of response processing will be explained below using the robot stop device 30 as an example.

[0116] In step S70 shown in Figure 18, the robot stop device 30 determines whether or not safe communication is possible with the device that sent the safe communication start command (e.g., stop device 20). If the robot stop device 30 determines that safe communication is possible (step S70: YES), it proceeds to step S71. On the other hand, if the robot stop device 30 determines that safe communication is not possible (step S70: NO), it terminates the process.

[0117] Specifically, the robot stop device 30 checks whether the received safety communication start command satisfies the following three conditions: (1) "SN" indicates "0: Init" (2) "ID" includes the identification information of all other devices in the group that wish to join, and the identification information of the stop device 20 that sent the safety communication start command (3) "DATA" includes the safety communication start request If the above three conditions are met, the robot stop device 30 determines that safety communication is possible and proceeds to step S71.

[0118] In step S71, the robot stop device 30 returns a response to the device that sent the safety communication start command. Then the process ends.

[0119] Next, the operation sequences of the secure communication establishment process and the response process will be explained using Figures 19 and 20.

[0120] As shown in Figure 19, the stop device 20, which wishes to join a group, intercepts communications from surrounding groups to search for a group it can join. Here, the stop device 20 extracts two groups, Group 1 and Group 2, and obtains a list of members for each group (e.g., Group 1 → Member 1: Stop device 20, Member 2: Robot stop device 30, Member 3: Robot stop device 30; Group 2 → Member 1: Stop device 20, Member 2: Robot stop device 30, Member 3: Robot stop device 30). This member list includes information on all other devices within the group (e.g., ID, status information, device type, etc.), and the stop device 20 can obtain this information before joining the group. Specifically, the stop device 20 dynamically obtains information on groups it can join using the network discovery protocol and service search function. This obtained information is incorporated into the secure communication start command and transmitted to all other devices within the group that wish to join. The stopping device 20 then selects Group 1, which is the closest to itself, as the group that wishes to participate, and sends a safety communication start command to all other devices within Group 1.

[0121] As shown in Figure 20, all other devices in Group 1 (e.g., Members 1-3) each perform the response processing shown in Figure 18 and return a response to the stop device 20 that wishes to join Group 1. Subsequently, as shown in Figure 8, the stop device 20 sends a request to join to all other devices in Group 1.

[0122] As described above, in the wireless communication system 10 according to the second embodiment, a predetermined stop device 20 or predetermined robot stop device 30 that wishes to join a group sends a safe communication start command to all of the one or more stop devices 20 and all of the one or more robot stop devices 30 that constitute the group before sending a participation request. Then, based on the fact that the stop device 20 or robot stop device 30 has received a response from all of the one or more stop devices 20 and all of the one or more robot stop devices 30 that received the safe communication start command, it sends a participation request to all of the one or more stop devices 20 and all of the one or more robot stop devices 30. As a result, according to the wireless communication system 10, the reliability of the participation request is improved by establishing safe communication before sending the participation request, and accurate and safe communication between devices in the group is guaranteed. Furthermore, according to the wireless communication system 10, participation requests are reliably transmitted, and the efficient and stable operation of the entire system is promoted.

[0123] In the second embodiment, if safety communication is established after the stop device 20 or robot stop device 30 sends a safety communication start command but before it sends a join request, it may omit sending the join request and immediately join the group. This eliminates the need to send unnecessary join requests and effectively reduces communication delays.

[0124] Furthermore, in the second embodiment, if the stop device 20 or robot stop device 30 fails to receive a response from all other devices in the group wishing to join after sending a safety communication start command, it may add special information when subsequently sending a participation request. Specifically, the stop device 20 or robot stop device 30 adds information to the participation request sent to the other devices, excluding the one that did not respond, inquiring whether communication with the other device that did not respond is possible. In this case, if no "communication possible" response is received, the device is considered to be malfunctioning, and the stop device 20 or robot stop device 30 is permitted to join the group even without permission from the malfunctioning device. This process makes it possible to achieve efficient group participation while minimizing the impact of potentially malfunctioning devices.

[0125] In the second embodiment, the stop device 20 or robot stop device 30 may dynamically change the restrictions applied to the communication content after joining the group, depending on whether a secure communication is established before sending a join request and the robot joins the group, or whether a join request is sent directly and the robot joins the group. Specifically, if a secure communication is established in advance, the stop device 20 or robot stop device 30 can assign a high-priority communication path within the group to minimize communication delays and packet loss, while if a direct join request is sent, it can assign a low-priority communication path. This approach optimizes the overall communication bandwidth and ensures that important communications are reliably performed, enabling efficient and reliable operation of the entire system.

[0126] (Other) Although embodiments of the present disclosure have been described in detail above with reference to the attached drawings, the technical scope of the present disclosure is not limited to these examples. It is clear that a person with ordinary skill in the art of the present disclosure may conceive of various modifications or alterations within the scope of the technical idea set forth in the claims, and it is understood that these modifications or alterations also fall within the technical scope of the present disclosure.

[0127] Furthermore, the effects described in the above embodiments are descriptive or illustrative, and are not limited to those described in the above embodiments. In other words, the technology relating to this disclosure may produce other effects that would be obvious to a person of ordinary skill in the art of this disclosure from the descriptions in the above embodiments, in addition to or in lieu of the effects described in the above embodiments.

[0128] The processing described in the above embodiment can also be implemented using dedicated hardware circuits. In this case, it may be executed on one piece of hardware or on multiple pieces of hardware.

[0129] In the wireless communication system 10, if a predetermined device joins a group without receiving permission to join from all other devices in the group, and that predetermined device is a robot stop device 30, it may transition itself to a safe state. In this case, the robot stop device 30, which is part of the other devices, may also transition itself to a safe state when it receives communication from the predetermined device.

[0130] In the wireless communication system 10, a group switching selector may be provided in the stop device 20 for switching (adding or changing) the groups for which stopping the robot is enabled. By operating the group switching selector, the user can switch the groups for which stopping the robot is enabled, and for example, stopping can be enabled for multiple groups.

[0131] In the above embodiment, safe communication between the stop device 20 and the robot stop device 30 was ensured by making the safety hardware of the stop device 20 and the robot stop device 30 redundant, but the configuration for ensuring safe communication is not limited to this. For example, in the wireless communication system 10, safe communication between the stop device 20 and the robot stop device 30 may be ensured by making the safety hardware of the stop device 20 and the robot stop device 30 a single configuration and making the software processing redundant.

[0132] In the above embodiment, the various processes executed by the control units 21 and 22 of the stop device 20 or the control units 31 and 32 of the robot stop device 30 after reading the software (program) may be executed by various processors other than the CPU. Examples of such processors include dedicated electrical circuits, which are processors with circuit configurations specifically designed to execute particular processes, such as FPGAs (Field-Programmable Gate Arrays), PLDs (Programmable Logic Devices) whose circuit configurations can be changed after manufacturing, and ASICs (Application Specific Integrated Circuits). Furthermore, the various processes may be executed by one of these various processors, or by a combination of two or more processors of the same or different types (for example, multiple FPGAs, and a combination of a CPU and an FPGA). Furthermore, the hardware structure of these various processors is, more specifically, an electrical circuit composed of circuit elements such as semiconductor devices.

[0133] Furthermore, although the above embodiment describes a configuration in which the program for executing the various processes is pre-stored (installed) in the storage units 23 and 24 of the stop device 20 and the storage units 33 and 34 of the robot stop device 30, the invention is not limited to this configuration. The program may be provided in a form recorded on a recording medium such as a CD-ROM (Compact Disk Read Only Memory), DVD-ROM (Digital Versatile Disk Read Only Memory), or USB (Universal Serial Bus) memory. The program may also be provided in a form that can be downloaded from an external device via a network. The technology of this disclosure can also be applied to programs and program products.

[0134] All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

[0135] The disclosures of Japanese Patent Application No. 2024-172782, filed on 1 October 2024, and Japanese Patent Application No. 2025-029439, filed on 26 February 2025, are incorporated herein by reference in their entirety.

[0136] The following are additional notes relating to this disclosure. (Additional Note 1) A wireless communication system comprising a plurality of transmitting devices and a plurality of receiving devices capable of wireless communication in accordance with safety standards for the plurality of transmitting devices, wherein each of the plurality of transmitting devices transmits stop information to each of the plurality of receiving devices via wireless communication to stop the equipment connected to each of the plurality of receiving devices based on receiving a stop instruction from a user, and each of the receiving devices stops the equipment connected to it based on receiving the stop information.

[0137] (Note 2) The wireless communication system according to Note 1, wherein each transmitting device comprises a first processor and a second processor that each generate the stop information, the first processor and the second processor confirm the stop information they have generated and then permit the transmission of the stop information to the plurality of receiving devices, each receiving device comprises a third processor and a fourth processor that each confirm the contents of the received stop information, and the third processor and the fourth processor confirm the stop information they have received and then stop the equipment connected to their own device.

[0138] (Appendix 3) The wireless communication system according to Appendix 2, wherein the first processor and the second processor generate the stop information which includes information that can identify the plurality of transmitting devices and the plurality of receiving devices.

[0139] (Note 4) The wireless communication system according to any one of Notes 1 to 3, wherein each transmitting device transmits the stop information to the transmitting devices other than itself among the plurality of transmitting devices and to the plurality of receiving devices, and the transmitting device that receives the stop information and each of the plurality of receiving devices return a response indicating the status of its own device to the transmitting device that transmitted the stop information.

[0140] (Note 5) A predetermined transmitting device and a predetermined receiving device can participate in a group consisting of one or more transmitting devices and one or more receiving devices capable of wireless communication with the one or more transmitting devices, and the predetermined transmitting device or the predetermined receiving device that wishes to participate in the group sends a participation request to all of the one or more transmitting devices and all of the one or more receiving devices that constitute the group, and the predetermined transmitting device or the predetermined receiving device joins the group and is permitted to communicate wirelessly between the devices in the group, as described in any one of Notes 1 to 4.

[0141] (Appendix 6) The wireless communication system according to Appendix 5, wherein the specified transmitting device and the specified receiving device are capable of leaving the group, and the specified transmitting device or the specified receiving device that wishes to leave the group transmits a departure request to all of the one or more transmitting devices and all of the one or more receiving devices that constitute the group, and the specified transmitting device or the specified receiving device leaves the group and wireless communication between the devices of the group is prohibited based on the receipt of permission to leave from all of the one or more transmitting devices and all of the one or more receiving devices that have received the departure request.

[0142] (Appendix 7) The wireless communication system according to Appendix 5 or Appendix 6, wherein a designated transmitting device or designated receiving device that wishes to join the group transmits a request to initiate the wireless communication to all of the one or more transmitting devices and all of the one or more receiving devices constituting the group before transmitting the request to join, and transmits the request to all of the one or more transmitting devices and all of the one or more receiving devices constituting the group based on the receipt of a response from all of the one or more transmitting devices and all of the one or more receiving devices that have received the request to initiate.

Claims

1. A wireless communication system comprising a plurality of transmitting devices and a plurality of receiving devices capable of wireless communication in accordance with safety standards for the plurality of transmitting devices, wherein each of the plurality of transmitting devices transmits stop information to each of the plurality of receiving devices via wireless communication to stop the equipment connected to each of the plurality of receiving devices upon receiving a stop instruction from a user, and each of the receiving devices stops the equipment connected to it upon receiving the stop information.

2. The wireless communication system according to claim 1, wherein each transmitting device comprises a first processor and a second processor that each generates the stop information, the first processor and the second processor confirm the stop information they have generated and then permit the transmission of the stop information to the plurality of receiving devices, each receiving device comprises a third processor and a fourth processor that each confirm the contents of the received stop information, and the third processor and the fourth processor confirm the stop information they have received and then stop the equipment connected to their respective devices.

3. The wireless communication system according to claim 2, wherein the first processor and the second processor generate the stop information which includes information that can identify the plurality of transmitting devices and the plurality of receiving devices.

4. The wireless communication system according to claim 1, wherein each transmitting device transmits the stop information to the other transmitting devices among the plurality of transmitting devices and to the plurality of receiving devices, and the transmitting device that received the stop information and each of the plurality of receiving devices return a response indicating the status of its own device to the transmitting device that transmitted the stop information.

5. A predetermined transmitting device and a predetermined receiving device can participate in a group consisting of one or more transmitting devices and one or more receiving devices capable of wireless communication with the one or more transmitting devices, the predetermined transmitting device or the predetermined receiving device wishing to participate in the group sends a participation request to all of the one or more transmitting devices and all of the one or more receiving devices constituting the group, and the predetermined transmitting device or the predetermined receiving device joins the group and is permitted to communicate wirelessly between the devices in the group, according to claim 1.

6. The predetermined transmitting device and predetermined receiving device are capable of leaving the group, and the predetermined transmitting device or predetermined receiving device that wishes to leave the group transmits a departure request to all of the one or more transmitting devices and all of the one or more receiving devices that constitute the group, and based on receiving permission to leave from all of the one or more transmitting devices and all of the one or more receiving devices that have received the departure request, the predetermined transmitting device or predetermined receiving device leaves the group and wireless communication between the devices of the group is prohibited, the wireless communication system according to claim 5.

7. The wireless communication system according to claim 5, wherein a predetermined transmitting device or predetermined receiving device that wishes to join the group transmits a request to initiate the wireless communication to all of the one or more transmitting devices and all of the one or more receiving devices constituting the group before transmitting the request to join, and transmits the request to all of the one or more transmitting devices and all of the one or more receiving devices constituting the group based on the receipt of a response from all of the one or more transmitting devices and all of the one or more receiving devices that have received the request to initiate.

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