WO2015016108A1

WO2015016108A1 - Robot control device

Info

Publication number: WO2015016108A1
Application number: PCT/JP2014/069417
Authority: WO
Inventors: 信博谷; 辰男工藤
Original assignee: 株式会社ダイヘン
Priority date: 2013-07-29
Filing date: 2014-07-23
Publication date: 2015-02-05
Also published as: CN105579202A; JP2015044280A; TWI679090B; CN105579202B; TW201515793A

Abstract

A robot control device (RC) comprises a switching hub (20) and a main CPU (10). A wireless access point (50) that wirelessly communicates with a wireless TP (100B) is connected to the switching hub (20) via a communications line (L1) and a wired TP (100A) is connected to the switching hub (20) via a communications line (L2). The main CPU (10) grants operation rights for permitting the operation of a robot (R), to either the wired TP (100A) or the wireless TP (100B). In this way, the TP having the operation rights granted thereto can be operated exclusively, by granting the operation rights to only either the wired TP (100A) or the wireless TP (100B), and stability can be ensured in a configuration whereby the wired TP and the wireless TP are shared.

Description

Robot controller

The present invention relates to a robot control device that transmits and receives various data to and from a portable operation device using network communication technology.

Patent Documents 1 to 4 disclose a system configured to perform wireless communication between a portable operation device called a teach pendant and a robot control device.
In the systems disclosed in Patent Literature 1 and Patent Literature 2, a wireless communication unit and a wired communication unit are provided inside the portable operating device. According to the systems disclosed in these documents, a wireless TP (wireless portable operating device) is connected to a controller that controls the operation of the robot via a cable. Thus, the wireless TP is used as a wired TP (wired portable operating device).

According to the system disclosed in Patent Document 3, the wired TP is connected via a cable to a wireless device that is wound around the operator's waist and held. Thereby, the wired TP is used as a wireless TP.

In the system disclosed in Patent Document 4, a wireless communication unit and a wired communication unit are provided inside a portable operation device. According to the system disclosed in this document, when the portable operation device is placed on a dedicated stand installed in the robot control device, the connection terminal of the portable operation device and the connection terminal of the robot control device are electrically connected. Connected to. Thereby, a portable operation device is used as wired TP.

Generally, the wireless TP is excellent in workability and portability because it is not necessary to route a cable. Further, it is superior to the wired TP in that one wireless TP can be used for a plurality of robot control devices. On the other hand, the wireless TP is inferior to the wired TP in that it is easily affected by the communication environment and cannot be used due to insufficient charging. These problems can be solved by adding a wireless communication unit to the wired TP or separately preparing a wireless device as described in Patent Documents 1 to 4. That is, the portable operating devices described in Patent Documents 1 to 4 are configured to be used as both a wired TP and a wireless TP.

By the way, the following two methods are conceivable when incorporating the advantages of wireless TP into existing facilities that use wired TP. That is, (1) a method of replacing the current wired TP with a wireless TP and (2) a method of adding a wireless function to the wired TP as described in Patent Documents 1 to 4.

However, the method (1) cannot solve the drawbacks such as being easily affected by the communication environment and being unable to be used due to insufficient charging. Further, in the method (2), since many parts are required to make the wired TP wireless, the weight of the portable operating device increases. Further, the configuration using the wireless device is a burden for the operator to always carry the wireless device. Therefore, in order to take advantage of both the wired TP and the wireless TP, the wired TP is not provided with a wireless function, but a wireless TP is added separately from the wired TP and the wired TP and the wireless TP are shared. Is the best.

However, inconvenience arises when both wired TP and wireless TP can be operated simultaneously. That is, if both the wired TP and the wireless TP are connected to a single robot controller and the robot can be operated from both the wired TP and the wireless TP, a safety problem arises. For this reason, the industrial robot must be configured such that one-to-one opposing communication is always performed between the robot control device and the portable operation device. In addition, the industrial robot needs to be configured so that it cannot be operated from other portable operation devices while being operated by an operator having the portable operation device.

However, in the above-described prior art, safety is not considered at all when a configuration in which a wired TP and a wireless TP are shared is adopted.

JP 2008-93743 A JP 2006-341356 A JP 2011-194504 A JP 2006-321014 A

An object of the present invention is to provide a robot control device capable of ensuring safety in a form in which a wired TP and a wireless TP are shared.

In order to solve the above problems, according to a first aspect of the present invention, there is provided a robot control device for controlling a robot in accordance with an operation of a portable operation device. A robot control device includes a wireless communication unit that performs wireless communication with a wireless portable operation device, a relay unit to which the wired portable operation device is connected via a communication line, a wired portable operation device, and a wireless portable operation device. One of these is provided with an operation right granting unit for granting an operation right for permitting operation of the robot.

In the above robot control device, it is preferable that the operation right granting unit grants the operation right to the portable operation device to which a connection request is first output among the wired portable operation device and the wireless portable operation device.

In the robot control device described above, a connection request is output from the other portable operation device to which either one of the wired portable operation device and the wireless portable operation device has been given the operation right and has not been given the operation right. If the current state of the robot or the robot control device satisfies the predetermined condition, and the current state satisfies the predetermined condition, the operation right granting unit confirms whether or not the other portable operation device It is preferable to give an operation right to.

In the above robot control device, when the operation right is given to the other portable operation device, the operation right giving unit preferably cuts off the servo power supply of the robot.
In the robot control device described above, a connection request is output from the other portable operation device to which either one of the wired portable operation device and the wireless portable operation device is given the operation right and is not granted the operation right. In this case, it is preferable that the operation right granting unit notifies the other portable operation device that there is a portable operation device to which the operation right has already been given.

In the above robot control device, it is preferable that the operation right granting unit cancels the operation right on the condition that a predetermined time has elapsed when the portable operation device to which the operation right is given is not operated.

The schematic diagram which shows the structure of the robot control system provided with the robot control apparatus of this invention (A) is a block diagram showing a configuration of a robot control system, (b) is a block diagram showing a configuration of a wired TP, and (c) is a block diagram showing a configuration of a wireless TP. Block diagram showing the configuration of the receiving unit of the robot controller Block diagram showing a state where a wired TP and a wireless TP are simultaneously connected to the receiving unit Flow chart of operation right grant processing

Hereinafter, an embodiment of a robot control device according to the present invention will be described with reference to FIGS.
As shown in FIG. 1, the robot control system 1 includes a robot R, a wired TP 100A and a wireless TP 100B, and a robot control device RC that controls the operation of the robot R. The robot R is a working robot that performs arc welding, spot welding, and the like. Work tools such as an arc welding torch and a spot welding gun are attached to the tip of the wrist of the robot R. The wired TP 100A is a wired portable operating device, and the wireless TP 100B is a wireless portable operating device.

The wired TP 100A and the wireless TP 100B include a microcomputer in which an operating system such as Windows (registered trademark) is incorporated. The wired TP 100A and the wireless TP 100B include a keyboard 130, a display device 140, an emergency stop switch 180, and the like. The operator operates the keyboard 130 to execute the teaching work of the robot R. The display device 140 displays the teaching data input by the teaching operation. The operator operates the emergency stop switch 180 to stop the robot R in an emergency. An enable switch (not shown) is attached to the back surfaces of the wired TP 100A and the wireless TP 100B. The operator operates the enable switch when operating in the teaching mode to supply or cut off power to the servo motor of the robot R.

The teaching operation signal from the wired TP 100A is transmitted to the robot controller RC by wired communication. The teaching operation signal from the wireless TP 100B is transmitted to the robot controller RC by wireless communication. The teaching operation signal includes a jog feed signal for moving the robot R by manual operation, a teaching signal for inputting teaching data, an emergency stop signal for enabling an emergency stop of the robot R in an emergency, an enable signal, and the like. . When these teaching operation signals are transmitted from the wired TP 100A or the wireless TP 100B, the robot controller RC performs various processes such as a jog feed operation of the robot R, creation of teaching data, and emergency stop.

As shown in FIG. 2A, the robot controller RC is connected to a main CPU (central processing unit) 10 serving as a control center, a switching hub 20 as a relay unit, a receiving unit 30, and a receiving unit 30. The sequence control unit 40 is provided. The switching hub 20 relays communication data from the wired TP 100 A and the wireless TP 100 B and transmits them to the main CPU 10 and the receiving unit 30, respectively.

The main CPU 10 calculates various processes according to the teaching operation signal from the wired TP 100A or the wireless TP 100B, specifically, input of teaching data, setting of control parameters, and the like. Further, the main CPU 10 calculates a current command of a drive motor provided at each joint of the robot R and outputs it to a servo amplifier (not shown). Thereby, the drive motor of each joint is driven. Further, the main CPU 10 gives an operation right for permitting the operation of the robot R to one of the wired TP 100A and the wireless TP 100B. That is, the main CPU 10 is an operation right grant unit, and controls so that only one of the wired TP 100A and the wireless TP 100B can be used exclusively.

The switching hub 20 has ports 21 to 24 for LAN connection. Examples of the LAN connection include, but are not limited to, a communication connection using Ethernet (registered trademark). The communication line L1 of the wireless access point 50 is attached to and detached from the port 21. The communication line L2 of the wired TP 100A is attached to and detached from the port 22. The port 23 is connected to the main CPU 10, and the port 24 is connected to the receiving unit 30. The wireless access point 50 performs wireless communication with the wireless TP 100B using a known communication protocol. The wireless access point 50 corresponds to a wireless communication unit.

As shown in FIG. 3, the receiving unit 30 includes a pair of

CPUs

31, 32, relays RY1, RY3 operated by the CPU 31, relays RY2, RY4 operated by the CPU 32, enable

output circuits

33, 34, and an emergency stop output.

Circuits

35 and 36 and

connection terminal portions

37, 38 and 39 are provided. An emergency stop signal and an enable signal from the wireless TP 100 B are input to the

CPUs

31 and 32 from the switching hub 20 via the connection terminal portion 37.

As shown in FIG. 4, an enable signal from the wired TP 100A is input to the

CPUs

31 and 32 via the connection terminals T21 to T24 of the connection terminal unit 38. The

CPUs

31 and 32 individually operate the relays RY1 to RY4 based on the input signals regardless of the presence or absence of input signals from other CPUs.

The enable

output circuits

33 and 34 are duplicated safety circuits. The enable output circuit 33 is a circuit in which relay contacts S 1 and S 2 composed of a contacts (normally open contacts) are connected in series, and is connected to the connection terminals T 1 and T 2 of the connection terminal portion 39. The connection terminals T1 and T2 are electrically connected to the connection terminals T11 and T12 of the sequence control unit 40, respectively. The enable output circuit 34 is a circuit in which relay contacts S3 and S4 made up of a contacts (normally open contacts) are connected in series, and is connected to the connection terminals T3 and T4 of the connection terminal portion 39. The connection terminals T3 and T4 are electrically connected to the connection terminals T13 and T14 of the sequence control unit 40, respectively. The relay contacts S1 and S3 are closed when the relay RY1 is activated (excited). The relay contacts S2 and S4 are closed when the relay RY2 is activated (excited).

The emergency

stop output circuits

35 and 36 are duplicated safety circuits. The emergency stop output circuit 35 includes a connection circuit that short-circuits between the connection terminal T5 of the connection terminal portion 39 and the connection terminal T25 of the connection terminal portion 38, and a series circuit of relay contacts S5 and S6. Each end of the series circuit of the relay contacts S5 and S6 is connected to the connection terminal T6 of the connection terminal portion 39 and the connection terminal T26 of the connection terminal portion 38, respectively. The connection terminals T5 and T6 are electrically connected to the connection terminals T15 and T16 of the sequence control unit 40, respectively. The emergency stop output circuit 36 includes a connection circuit that short-circuits between the connection terminal T7 of the connection terminal portion 39 and the connection terminal T27 of the connection terminal portion 38, and a series circuit of relay contacts S7 and S8. Each end of the series circuit of the relay contacts S7 and S8 is connected to the connection terminal T8 of the connection terminal portion 39 and the connection terminal T28 of the connection terminal portion 38, respectively. The connection terminals T7 and T8 are electrically connected to the connection terminals T17 and T18 of the sequence control unit 40, respectively. The relay contacts S5 and S7 are b contacts (normally closed contacts) and open when the relay RY3 is activated (excited). The relay contacts S6 and S8 are b contacts (normally closed contacts) and open when the relay RY4 is activated (excited).

When at least one relay contact is opened after all of the relay contacts S1 to S4 of the enable

output circuits

33 and 34 are closed, the sequence control unit 40 receives an enable signal from the enable

output circuits

33 and 34 with the relay contacts open. A cutoff signal based on this is input. As a result, the sequence control unit 40 operates a circuit breaker (not shown) to cut off power supply to a servo amplifier (not shown). That is, the power supply to the servo motor that is the drive source of the robot R is cut off.

Further, at least one of the connection terminals T25 and T26 and the connection terminals T27 and T28 is changed from a short circuit state to a non-short circuit state, or at least one relay of the relay contacts S5 to S8 of the emergency

stop output circuits

35 and 36. When the contact is opened, the sequence control unit 40 operates a circuit breaker (not shown) to cut off power supply to a servo amplifier (not shown). The power supply to the servo motor is described as “servo power on” and the power supply cut-off to the servo motor is described as “servo power off”.

The connection terminals T21 to T24 of the connection terminal part 38 are electrically connected to the connection terminals T31 to T34 of the connection terminal part 42 of the robot controller RC, respectively. The connection terminals T25 to T28 of the connection terminal part 38 are electrically connected to the connection terminals T35 to T38 of the connection terminal part 42 of the robot controller RC, respectively.

First, the wired TP 100A will be described with reference to FIG.
As shown in FIG. 2B, the wired TP 100A includes a CPU (central processing unit) 110, a ROM 120, a keyboard 130, a display device 140, and a wired LAN I / F (interface) 150. Each unit such as a CPU (central processing unit) 110, a ROM 120, a keyboard 130, a display device 140, and a wired LAN I / F (interface) 150 is connected to each other via a bus 190. The wired LAN I / F 150 is attached to and detached from the port 22 of the switching hub 20 via the communication line L2. The wired TP 100A can communicate with the main CPU 10 of the robot controller RC via the communication line L2 and the switching hub 20. As communication data in this case, various data such as key information generated in response to an operation of the keyboard 130 from the wired TP 100A, screen information of the display device 140, and the like can be given.

The wired TP 100A includes an enable switch 170 and an emergency stop switch 180. As shown in FIG. 4, when the enable switch 170 is turned on, the normally open contacts S11 and S12 provided in each of the pair of circuits C1 and C2 are closed, and when the enable switch 170 is turned off, the normally open contacts S11 and S12 are normally opened. The contacts S11 and S12 are opened. When the wired TP 100A is used, the circuits C1 and C2 are connected to the connection terminals T31 to T34 of the connection terminal portion 42 of the robot controller RC via the signal line L3 and a plug (not shown). When the signal line L3 is connected to the connection terminal portion 42 and the normally open contacts S11 and S12 are opened from the closed state, enable signals are output from the circuits C1 and C2 to the robot controller RC, respectively.

When the emergency stop switch 180 is turned off, the normally closed contacts S13 and S14 provided in each of the pair of circuits C3 and C4 are opened. The circuits C3 and C4 are connected to the connection terminals T35 to T38 of the connection terminal portion 42 of the robot controller RC via the signal line L3 and a plug (not shown). When the emergency stop switch 180 is turned off with the circuits C3 and C4 connected to the robot controller RC, both normally closed contacts S13 and S14 are opened, and an emergency stop signal is sent from the circuits C3 and C4 to the robot controller RC. Each is output.

Next, the wireless TP 100B will be described with reference to FIG. A detailed description of the same parts of the wireless TP 100B as those of the wired TP 100A will be omitted.
As shown in FIG. 2C, the wireless TP 100B is different from the wired TP 100A in that it has a wireless LAN I / F 160 instead of the wired LAN I / F 150. As shown in FIG. 2A, the wireless TP 100B can communicate wirelessly with the main CPU 10 of the robot controller RC via the wireless access point 50, the communication line L1, and the switching hub 20. Examples of communication data in this case include key information generated in response to an operation of the keyboard 130 from the wireless TP 100B, various data such as screen information of the display device 140, and the like.

Although not shown, the wireless TP 100B has a configuration corresponding to the circuits C1 to C4, the normally open contacts S11 and S12, and the normally closed contacts S13 and S14. In the wireless TP 100B, unlike the wired TP 100A, when the enable switch 170 is operated to close the pair of normally open contacts S11 and S12, the wireless LAN I / F 160 outputs an enable signal wirelessly. When the emergency stop switch 180 of the wireless TP 100B is operated to open the pair of normally closed contacts S13 and S14, the wireless LAN I / F 160 outputs an emergency stop signal wirelessly.

The operation of the robot controller RC will be described with reference to the flowchart of FIG. Specifically, a process when the main CPU 10 gives an operation right to only one of the wired TP 100A and the wireless TP 100B will be described. In the description, the wired TP 100A is referred to as a wired TP, and the wireless TP 100B is referred to as a wireless TP.
(1. When neither the wired TP nor the wireless TP has established communication with the robot controller RC and the operation right for permitting the operation of the robot R is not granted)
First, a process when a connection request is output from the wired TP in a state where neither the wired TP nor the wireless TP is given an operation right will be described.

As shown in FIG. 5, in step St1, the main CPU 10 confirms whether or not there is a connection request. After confirming the connection request from the wired TP (step St1: Yes), the main CPU 10 proceeds to step St2.

In step St2, the main CPU 10 confirms the operation right grant state. When an operation right is given to one of the wired TP and the wireless TP, identification information such as a MAC address is stored in a RAM (not shown) of the robot controller RC. In this case, the main CPU 10 reads the identification information from the RAM and confirms the operation right granting state. Here, since the operation right is not given to either the wired TP or the wireless TP, the identification information is a NULL value.

In step St3, the main CPU 10 determines which of the wired TP and the wireless TP has the operation right based on the identification information read from the RAM. Here, since the identification information is a NULL value, the main CPU 10 determines that no operation right is given to either the wired TP or the wireless TP (step St3: No), and then proceeds to step St8.

In step St8, the main CPU 10 grants an operation right to the wired TP from which the connection request is output. Further, the main CPU 10 stores the identification information of the wired TP to which the operation right is given in a RAM (not shown) of the robot control device RC.

In step St9, the main CPU 10 performs processing for establishing communication with the wired TP. After the communication is established, the main CPU 10 notifies the wired TP that the operation right is given to the wired TP. As a result, a message indicating that the operation right is given is displayed on the wired TP display device 140.
(2. When a connection request is output from the other TP to which no operation right is granted while one of the wired TP and the wireless TP has the operation right)
Next, a process when a connection request is output from the other TP to which no operation right is granted while one of the wired TP and the wireless TP is given an operation right will be described. Here, a process when a connection request is output from the wireless TP in a state where the operation right has already been given to the wired TP will be described.

In step St1, the main CPU 10 confirms whether there is a connection request. After confirming the connection request from the wireless TP (step St1: Yes), the main CPU 10 proceeds to step St2.

In step St2, the main CPU 10 reads the identification information from the RAM in order to confirm the operation right granting state. Here, the identification information of the wired TP is read from the RAM.

In step St3, the main CPU 10 determines which of the wired TP and the wireless TP has the operation right based on the identification information read from the RAM. Here, the main CPU 10 determines that the operation right is given to the wired TP (step St3: No), and then proceeds to step St4. At this time, the main CPU 10 notifies the wireless TP from which the connection request is output that the operation right has already been granted to the wired TP.

In step St4, the main CPU 10 confirms the operating right delegation condition. That is, the main CPU 10 determines whether or not the operation right can be transferred from the wired TP to the wireless TP. The main CPU 10 reads out internal variables, flags, etc. to determine whether or not the operation right can be delegated, and confirms the current state of the robot R or the robot controller RC. For example, when the current state of the robot R or the robot control device RC satisfies the following conditions, the main CPU 10 determines that the operation right cannot be delegated. However, the following conditions are examples and are not limited to these.

• The teaching mode and the servo power of the robot R are on.
• Power is supplied to the servo amplifier in the teaching mode.
-The external storage device provided in the TP is being accessed (reading / writing).

-A lock function is set by the operator to prevent the operation right from being transferred to another TP.
In step St5, the main CPU 10 determines whether or not the operation right can be delegated. Here, it is assumed that the current state of the robot R or the robot controller RC does not satisfy any of the above conditions. In this case, the main CPU 10 determines that the operation right can be delegated (step St5: Yes), and proceeds to step St6. If the current state of the robot R or the robot controller RC satisfies any of the above conditions, the main CPU 10 determines that the operation right cannot be delegated (step St5: No), and ends this process.

In step St6, the main CPU 10 cancels the right to operate the wired TP currently connected to the robot controller RC and cuts off the communication with the wired TP. Note that the release of the operation right means that the identification information written in the RAM of the robot controller RC is cleared.

In step St7, the main CPU 10 turns off the servo power supply of the robot R. In this case, it is preferable that the servo power supply cannot be turned on immediately by cutting off the power supply to the servo amplifier. By doing in this way, even if the enable switch 170 is erroneously turned on at the TP immediately after the operation right is given, it is possible to prevent the servo power source from being turned on.

In step St8, the main CPU 10 grants an operation right to the wireless TP from which the connection request is output. That is, the main CPU 10 stores the identification information of the wireless TP to which the operation right is given in a RAM (not shown) of the robot control device RC.

In step St9, the main CPU 10 performs processing for establishing communication with the wireless TP. After establishing the communication, the main CPU 10 notifies the wireless TP that the operation right is given to the wireless TP. As a result, a message indicating that the operation right is given is displayed on the display device 140 of the wireless TP.
(3. Processing after granting operation rights)
The main CPU 10 executes various processes based only on the teaching operation signal from the TP to which the operation right is given. That is, the main CPU 10 interprets only the teaching operation signal from the TP to which the operation right is given, while ignoring the teaching operation signal from the TP to which the operation right is not given. In the present embodiment, the wired TP is always connected to the robot control device RC. Therefore, as shown in FIGS. 3 and 4, the emergency stop signal from the emergency stop switch 180 of the wired TP is transmitted to the sequence control unit 40 via the communication line L3 and the receiving unit. That is, only the emergency stop signal from the wired TP can be always input to the sequence control unit 40 regardless of the operation right. This means that while the operation right is given to the wireless TP, an operation signal from the wired TP is not input, but only the emergency stop switch 180 of the wired TP can be input. That is, the wired TP can function only as an emergency stop switch.

According to this configuration, a skilled person can operate a wireless TP by a beginner who is not familiar with the operation while having a wired TP that functions only as an emergency stop switch. In this case, even if the beginner jogs the robot R in the wrong direction, the skilled person can emergency stop the robot R by operating his own wired TP.

In this embodiment, the operation right may be forcibly released on condition that a predetermined time, for example, 10 minutes elapses, when the TP to which the operation right is granted is not operated. According to this configuration, since the operation right is not transferred from the TP to which the operation right is granted, the operation right is transferred after a predetermined time has elapsed even if the operator sets the lock function and then leaves the site. Can do.

As described above, according to the present embodiment, the operation right is given to only one of the wired TP and the wireless TP in a form in which the wired TP and the wireless TP are shared, so that the TP to which the operation right is granted can be exclusively used. Can be operated. Thereby, the safety | security in the form which shares wired TP and wireless TP is securable.

Claims

In a robot control device that controls a robot according to an operation of a portable operation device,
A wireless communication unit that performs wireless communication with the wireless portable operation device, and a relay unit to which the wired portable operation device is connected via a communication line, and
A robot control apparatus comprising: an operation right granting unit that grants an operation right for permitting operation of the robot to either one of the wired portable operation apparatus and the wireless portable operation apparatus.
The robot control device according to claim 1,
The operation right granting unit grants the operation right to a portable operation device to which a connection request is first output from the wired portable operation device and the wireless portable operation device. .
The robot control device according to claim 1 or 2,
When a connection request is output from the other portable operation device to which either one of the wired portable operation device and the wireless portable operation device has the operation right and the operation right is not granted The operation right granting unit checks whether or not the current state of the robot or the robot control device satisfies a predetermined condition, and if the current state satisfies the predetermined condition, the other portable type A robot control device characterized in that the operation right is given to an operation device.
The robot control device according to claim 3, wherein
The robot control apparatus, wherein when the operation right is given to the other portable operation device, the operation right grant unit cuts off a servo power supply of the robot.
The robot control device according to any one of claims 1 to 4,
When a connection request is output from the other portable operation device to which the operation right is not granted in a state where the operation right is given to any one of the wired portable operation device and the wireless portable operation device, The robot operation apparatus, wherein the operation right granting unit notifies the other portable operation apparatus that there is a portable operation apparatus to which an operation right has already been given.
The robot control device according to any one of claims 1 to 5,
The robot control apparatus according to claim 1, wherein the operation right granting unit releases the operation right on condition that a predetermined time has elapsed after the portable operation device to which the operation right is given has not been operated.