JP4064865B2 - Teaching pendant safety device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a teaching pendant used for setting operation contents to be executed by a mechanical device such as an industrial robot that is a teaching device, and in particular, whether to enable a teaching signal based on an operation of a deadman switch. The present invention relates to an enable device for a teaching pendant.
[0002]
[Prior art]
Operation teaching operations at the initial stage and during adjustment of a mechanical device such as an industrial robot are performed by operating a portable teaching pendant. At the time of teaching work, the operator must operate the teaching pendant gripped with both hands in the vicinity of the moving part of the mechanical device, and a serious accident such as failure of the mechanical device (teaching device) or misoperation of the teaching pendant You are exposed to dangers that lead to
[0003]
As a means for avoiding the danger of the operator when an abnormality occurs during the teaching operation for such a mechanical device, the teaching pendant is provided with an enabling device for selectively enabling the output of the teaching signal. . The enable device includes an operable switch disposed on the teaching pendant together with an operating switch that receives an instruction input for outputting a teaching signal to the mechanical device. This operable switch is also called a deadman switch, and can be operated only while the operator holds the teaching pendant in a predetermined posture. That is, only when the deadman switch is operated, the teaching signal based on the operation of the operation switch that is turned on is validated, and the teaching work for the mechanical device becomes possible (see, for example, Patent Documents 1 and 2).
[0004]
By providing the teaching pendant with the enable device, the operator can press the operation switch while the deadman switch is pressed and turned on to teach the operation to the mechanical device. If the machine device performs an operation that is not intended by the operator due to an operation error, etc., the operator releases the finger from the deadman switch or releases the teaching pendant, so that the deadman switch is turned off and an operation signal to the machine device Can be disabled and the machine can be stopped.
[0005]
However, when the mechanical device performs an operation not intended by the worker, the worker's actions include not only releasing the finger from the deadman switch and releasing the teaching pendant, but also pushing the deadman switch more strongly, May be tightened more strongly. Therefore, as a deadman switch, a normal two-position switch that simply turns on / off in accordance with the presence or absence of pressing is insufficient.
[0006]
For this reason, in the conventional teaching pendant, when it is lightly pushed from the first position in the OFF state where no pressing operation is performed (during non-operation) (in the middle operation), it is displaced to the second position in the ON state, and further from this second position. A three-position switch that is displaced to the third position in the OFF state when pressed in strongly (during complete operation) is used as a deadman switch. The three-position deadman switch returns from the third position to the first position without passing through the second position in the ON state. Because it is necessary for the machine device to stop operating completely until the worker who pushed the deadman switch to the 3rd position to release the danger finishes releasing the finger from the deadman switch after stopping the machine device. is there.
[0007]
For example, as shown in FIG. 3, the teaching pendant enable device 100 includes a first circuit C11, a second circuit C12, and a third circuit C13, each having three normally open contacts and one normally closed. Two relays R11 and R12 having contacts are provided. When the enable device 100 is in a normal state, when at least one of the right-hand deadman switch 101a and the left-hand deadman switch 101b is operated to the second position and is turned on, for example, the enable device 100 is connected to the safety relay module 120 of the mechanical device. An enable signal is output from the first circuit C11 and the second circuit C12. The safety relay module 120 enables the teaching signal only when the enable signal is input from both the first circuit C11 and the second circuit C12, and the operator can perform the teaching operation of the mechanical device.
[0008]
The first circuit C11 is a parallel circuit in which one main contact sw11a of the right-hand deadman switch 101a and one main contact sw11b of the left-hand deadman switch 101b are connected in parallel to the normally-open contact R111 of the relay R11 and the relay R12. The open contact R121 is connected in series.
[0009]
The second circuit C12 is a parallel circuit in which the other main contact sw12a of the right-hand deadman switch 101a and the other main contact sw12b of the left-hand deadman switch 101b are connected in parallel, and the normally-open contact R112 of the relay R11 and the relay R12 are always connected. The open contact R122 is connected in series.
[0010]
In the third circuit C13, the monitoring normally closed contact msw11a of the right-hand deadman switch 101a, the monitoring normally closed contact msw11b of the left-hand deadman switch, the normally closed contact R114 of the relay R11, and the normally closed contact R124 of the relay 12 are connected in series. The series circuit, the normally closed contact msw12a for the right-hand deadman switch 101a, the normally closed contact msw12b for the left-hand deadman switch, the normally open contact R113 of the relay R11 and the normally open contact R123 of the relay 12 are connected in series. A series circuit, these two series circuits are connected in parallel, and a parallel circuit of a relay R11 and a relay R12 is further connected in series.
[0011]
In each of the relays R11 and R12, the normally open contact R113, the normally closed contact R114, the normally open contact R123, and the normally closed contact R124 have a forced guide type relay configuration that switches simultaneously. Therefore, in the relay R11, when the normally open contact R113 is turned ON, the normally closed contact R114 is always turned OFF. In the initial state where the deadman switches 101a and 101b are not operated, the relays R11 and R12 are excited by the self-holding function, the normally open contacts R111 to R113 and R121 to R123 are turned on, and the normally closed contact R114. And R124 is turned OFF.
[0012]
In the above configuration, when the right-hand deadman switch 101a is operated from the initial state to the second position to be in the ON state, the main contacts sw11a and sw12a of the right-hand deadman switch 101a are turned on as shown in FIG. Although the normally closed contact msw11a is turned off, the energized states of the circuits C11 to C13 are maintained by the self-holding function of the relays R11 and R12. As a result, an enable signal is output from the first circuit C11 and the second circuit C12, and the operator can perform the teaching operation of the mechanical device.
[0013]
At this time, when the operator feels danger, for example, when the left-hand deadman switch 101b is pushed to the third position to be in the OFF state, as shown in FIG. 5, the monitoring circuit of the left-hand deadman switch 101b is normally closed in the third circuit C13. The contacts msw11b and msw12b are turned off, the energization of the third circuit C13 is cut off, and the relays R11 and R12 are demagnetized. As a result, the normally open contacts R111 to R113 of the relay R11 and the normally open contacts R121 to R123 of the relay R12 are turned OFF, the energization of the first circuit C11 and the second circuit C12 is also cut off, and the enable signal is not output. It becomes impossible to teach.
[0014]
From this state, the pushing force to the left-hand deadman switch 101b is released with the right-hand deadman switch 101a kept in the ON state, the left-hand deadman switch 101b returns to the first position, and the normally closed contacts sw11b and sw12b are sequentially turned on. Even in the ON state, as shown in FIG. 6, since the normally closed contact msw11a for monitoring of the right-hand deadman switch 101a is OFF and the normally open contacts R113 and R123 of the relays R11 and R12 are OFF, the relay R11 And the demagnetized state of R12 is maintained. As a result, the energization of the first circuit C11 and the second circuit C12 remains cut off, the ON state of the right-hand deadman switch 101a is not validated, and the non-teaching state is continued.
[0015]
Here, when the pushing force on the right-hand deadman switch 101a is released, the right-hand deadman switch 101a returns to the first position, and the monitoring normally closed contact msw11a of the right-hand deadman switch 101a is turned on. As a result, the circuits C11 to C13 are energized and the relays R11 and R13 are energized to return to the initial state shown by the solid line in FIG. 3, so that the right-hand deadman switch 101a or the left-hand deadman switch 101b is operated to the second position. This enables teaching of the mechanical device.
[0016]
In the configuration shown in FIG. 3, for example, when the contacts R111 to R114 of the relay R11 are welded while the left-hand deadman switch 101b is ON, the right-hand deadman switch 101a is operated to the third position. Even in the OFF state, the ON state of the normally open contacts R111 to R113 of the relay R11 and the OFF state of the normally closed contact R114 are maintained. However, since the normally open contacts R121 to R123 of the relay R12 are OFF and the energization of the circuits C11 to C13 is cut off, even if the right-hand deadman switch 101a is returned to the first position, the left-hand deadman switch 101b The ON state is not validated and it is possible to prevent the teaching of the mechanical device.
[0017]
In this state, even if both the deadman switches 101a and 101b are returned to the first position, the cut-off state in the third circuit C13 is maintained, and either the deadman switch 101a or 101b is pushed to the second position. Even if it is in the ON state, it cannot be in the teaching enable state. Therefore, when welding occurs at one of the contacts of the relay R11 or R12, the enable signal is not output even after both deadman switches 101a and 101b are returned to the first position. The occurrence of a fault is easily recognized.
[0018]
Further, when the safety relay module 120 detects a mismatch between the open / close states of the first circuit C11 and the second circuit C12, each of the first circuit C11 and the second circuit C12 includes one normally open contact. Thus, in the relays R11 and R12, either the normally open contact R111 or R112 and either the normally open contact R121 or R122 can be omitted. In this case, when contact welding occurs in the enable device 100, it is accurately recognized from the detection result of the safety relay module 120 whether the contact welding has occurred in the first circuit C11 or the second circuit C12.
[0019]
[Patent Document 1]
Japanese Utility Model No. 60-153787 microfilm
[Patent Document 2]
JP 2002-059383 A
[0020]
[Problems to be solved by the invention]
However, in the configuration shown in FIG. 3, the contact welding generated at one main contact of any one of the deadman switches cannot be detected, and the teaching operation of the mechanical device by the teaching pendant where the failure has occurred is continued. If contact welding occurs on the other main contact of the deadman switch, the mechanical device cannot be stopped unless one of the deadman switches is operated to the third position, thereby avoiding the danger of the operator when an abnormality occurs. There is a problem that makes it impossible.
[0021]
For example, as shown in FIG. 7, even when the right-hand deadman switch 101a is operated to the second position and one main contact sw11a is welded, at least one of the deadman switches is moved to the third position. By pushing, the monitoring circuit C13 is opened, the relays R11 and R12 are demagnetized, and the normally open contacts R111 to R113 and R121 to R123 can be turned off, so that no enable signal is output from the enable signal circuits C11 and C12. Since the operation of the mechanical device can be stopped via the safety relay module 120, the safety of the worker can be ensured when an abnormality occurs.
[0022]
However, even if both deadman switches 101a and 101b are subsequently returned to the first position, as shown in FIG. 8, the enable signal continues to be output from one of the enable signal circuits C11, and the safety relay module 120 This waits for the output of the enable signal from the enable signal circuit C12. For this reason, as shown in FIG. 9, next, when either one of the deadman switches 101a and 101b (the right-hand deadman switch 101a in FIG. 9) is operated to the second position, the main contact sw12a or sw12b (in FIG. 9) When welding occurs at the main contact sw12a), both the deadman switches 101a and 101b are in the first position, or when one is in the second position and the other is in the first position, the enable signal circuit C1 and The enable signal is output from both of C2, and the operation of the mechanical device cannot be stopped.
[0023]
As described above, in the configuration shown in FIG. 3, it is impossible to detect that the main contact of the deadman switch, which is a single failure, has occurred before the next teaching work. There was a problem that could not be secured.
[0024]
The object of the present invention is to determine whether or not the mismatch of the output states of the enable signals output in multiple continues for a predetermined time or longer, thereby preventing the welding of the main contact of the deadman switch that is a single failure. It can be detected quickly before the teaching work, and by making the operator recognize this state, the teaching work is not continued using the teaching pendant in which the failure has occurred, and the safety of the worker is improved. An object of the present invention is to provide a safety device for a teaching pendant that can be reliably secured.
[0025]
[Means for Solving the Problems]
The present invention has the following configuration as means for solving the above problems.
[0026]
  (1) An enable signal for enabling a teaching signal for a mechanical device according to an operating state of a deadman switch that is in a first OFF state when not operated, is turned on when an intermediate operation is performed, and is turned off when a complete operation is performed. Used in teaching pendants with multiple enable signal circuits for selective output,
  Determining means for determining whether or not all output states of the plurality of enable signals from the plurality of enable signal circuits match each other;
  A timing unit that starts when the discriminating unit detects a mismatch in the output states of the plurality of enable signals and starts timing, and resets when the discrepancy in the output state is no longer detected;
  An abnormality notifying means for notifying the occurrence of an abnormality in the teaching pendant when the time measuring means is timed up according to a predetermined time set in advance;
  Having establishedIt is characterized by.
[0027]
  In this configuration, when the output state of the plurality of enable signals output from each of the plurality of enable signal circuits does not coincide with each other for a predetermined time or longer according to the operation state of the deadman switch, an abnormality has occurred in the deadman switch. To be judged. Therefore, for example, when two enable signal circuits are provided in the teaching pendant, when only one of the enable signals is continuously output for a predetermined time or more, the output of the other enable signal is waited. Therefore, it is determined that an abnormality has occurred immediately, so that unless the abnormality is resolved, the teaching signal for the mechanical device is not validated no matter how the deadman switch is operated thereafter.
  At this time, in this configuration, when the discriminating means detects the mismatch of the output states of the plurality of enable signals, it starts the time measuring means for measuring a predetermined time, and when the time measuring means is timed up, the abnormality notifying means teaches The occurrence of an abnormality in the pendant is notified. Therefore, it is possible to accurately detect the occurrence of an abnormality in the teaching pendant as a cause of a mismatch between the output states of a plurality of enable signals for a predetermined time or more with a simple configuration including a discrimination means, a timing means, and an abnormality notification means. Is done.
[0028]
(2) The deadman switch includes a plurality of main contacts that are turned off in a non-operation state and a complete operation state and turned on in an intermediate operation state;
The teaching pendant safety device according to claim 1, wherein each of the plurality of enable signal circuits includes one main contact of the deadman switch.
[0029]
In this configuration, when the output states of the plurality of enable signals based on the ON / OFF states of the plurality of main contacts according to the operation state of the deadman switch do not coincide with each other for a predetermined time or longer, an abnormality is detected in the deadman switch. Judged to have occurred. Therefore, contact welding occurring at one of the main contacts of the deadman switch is accurately detected after a predetermined time has elapsed, and it is ensured that the teaching operation for the machine device is continued in a state where welding has occurred at one main contact. To be prevented.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
1A and 1B are a front view and a rear view of a teaching pendant to which an enable device according to an embodiment of the present invention is applied. A display panel 11 such as an LCD is arranged at the center of the front surface of the case of the teaching pendant 10. A plurality of transparent operation keys 12 are provided on the transparent touch switch at both end portions on the upper surface of the display panel 11. The operation key 12 is displaced downward during a pressing operation and turns on a touch switch arranged on the upper surface of the display panel 11. A plurality of push button switches 13 are arranged above the display panel 11 in front of the teaching pendant 10. The operation key 12 and the push button switch 13 correspond to the operation switch of the present invention, and receive an instruction input for outputting an operation signal assigned thereto. In particular, the operation key 12 is assigned the contents of the switch image in each screen displayed on the display panel 11. The display panel 11 itself can also be used as an operation switch by a touch panel.
[0033]
Grip bodies 14 a and 14 b are formed on the left and right side portions of the teaching pendant 10. At the time of teaching operation of an operation to a teaching apparatus such as an industrial robot (not shown), an operator holds the teaching pendant 10 with both hands on the gripping bodies 14a and 14b from both sides, and the operation key 12 or push button switch is mainly operated with the thumb. 13 is operated. The teaching pendant 10 is connected to the control circuit of the teaching device via a cable 18, and an operation signal assigned to the operation key 12 or the push button switch 13 operated by the operator is used as a teaching signal to control the teaching device. Input to the circuit.
[0034]
Concave portions 15a and 15b are formed on the back surface of the housing of the teaching pendant 10 continuously with the grip bodies 14a and 14b, and at the corners formed between the grip bodies 14a and 14b and the concave portions 15a and 15b. Deadman switches 101a and 101b are arranged. The deadman switch 101a is a right-hand deadman switch attached to the right-hand operation position where four fingers except the thumb of the right hand of the operator holding the right grip 14a as viewed from the front of the pendant 10 face each other. The deadman switch 101b is a left-hand deadman switch that is attached to the left-hand operation position where the four fingers other than the thumb of the left hand of the operator holding the left grip 14b as viewed from the front of the pendant 10 face each other.
[0035]
Each of the deadman switches 101a and 101b is a three-position switch. The first contact position of the main contact is in the non-operation state, the second position in which the main contact is lightly pushed in from the first position, and the second position is strong. When the operating force is released from the third position, the position is returned to the first position without going through the second position.
[0036]
As shown in FIG. 3 as an example, the teaching pendant 10 incorporates an enable device 100 including two enable signal circuits C11 and C12 according to the operating state of the deadman switches 101a and 101b. Two enable signals are output. Note that the enable device 100 incorporated in the teaching pendant 10 is not limited to that shown in FIG. 3, and a plurality of enable signal circuits each including a plurality of main contacts of a single or a plurality of deadman switches. Any configuration can be used as long as an enable signal is output in accordance with the operating state of the deadman switch.
[0037]
FIG. 2 is a block diagram showing the configuration of the safety device according to the embodiment of the present invention. The safety device 20 of the present invention comprises an EX-OR circuit 21 which is a discriminating means of the present invention, a timer circuit 22 which is the time measuring means, and an alarm circuit 23 which is the notification means. It is provided in the safety relay module 120 constituting a part. The EX-OR circuit 21 receives two enable signals s1 and s2 output from the teaching pendant 10 and outputs a detection signal when the two enable signals s1 and s2 do not match.
[0038]
The timer circuit 22 includes a counter circuit 22a, a preset circuit 22b, and a clock pulse oscillation circuit 22c. The counter circuit 22a reads the count value set in the preset circuit 22b when the detection signal is output from the EX-OR circuit 21, and decrements the count value every time the clock pulse is input from the clock pulse oscillation circuit 22c. To do. The counter circuit 22a is reset when the detection signal is no longer output from the EX-OR circuit 21, and outputs a time-up signal when the count value becomes “0”.
[0039]
The counter circuit 22a may be configured to increment the count value by a clock pulse from the clock pulse oscillation circuit 22c when a detection signal is output from the EX-OR circuit 21. In this case, when the count value of the counter circuit 22a matches the count value set in the preset circuit 22b, the timer circuit 22 outputs a time-up signal.
[0040]
When the time-up signal is input from the timer circuit 22, the alarm circuit 23 sounds and notifies the occurrence of an abnormality in the teaching pendant 10. Note that a warning display circuit may be provided in place of the alarm circuit 23 or together with the alarm circuit 23.
[0041]
With this configuration, in the enable device 100 shown in FIG. 3, when one main contact sw11a of the right-hand deadman switch 101a included in the one enable signal circuit C11 is contact-welded, the deadman switches 101a and 101b After any one of them is operated to the third position (during complete operation), the enable signal continues to be output only from the enable signal circuit C11 without the enable signal being output from the enable signal circuit C12 (see FIG. 8). When a predetermined time counted by the timer circuit 22 elapses, the alarm circuit 23 sounds.
[0042]
As a result, the operator can immediately recognize the occurrence of an abnormality in the teaching pendant 10, and the occurrence of a single failure in the teaching pendant 10 is quickly detected. For this reason, it is possible to prevent the teaching work for the teaching target device (mechanical device) from being performed by the teaching pendant 10 in which an abnormality has occurred, and to ensure the safety of the worker more reliably.
[0043]
The predetermined time counted by the timer circuit 22 can be set by a preset value stored in the preset circuit 22b, and is longer than the error time of the operation timings of the two main contacts in each of the normal deadman switches 101a and 101b. It is a short enough time to be satisfied with the time.
[0044]
In the above example, the safety device 20 of the present invention is provided in the safety relay module 120 that constitutes the control circuit of the taught device. However, the safety device 20 is incorporated in the teaching pendant 10 to provide the teaching pendant. 10 can be notified at a position closer to the operator. In this case, a warning lamp may be turned on as a notification unit, or a warning message may be displayed on the display panel 11 to visually notify the operator of the occurrence of an abnormality. In this case, the safety device 20 can also be configured using a microcomputer built in the teaching pendant 10.
[0045]
【The invention's effect】
According to the present invention, the following effects can be obtained.
[0046]
(1) It is determined that an abnormality has occurred in the deadman switch when the output states of the plurality of enable signals output from each of the plurality of enable signal circuits do not coincide with each other for a predetermined time or longer according to the operating state of the deadman switch. Thus, for example, in the case where two enable signal circuits are provided in the teaching pendant, when only one of the enable signals is continuously output for a predetermined time or more, the output of the other enable signal is waited. It is possible to immediately determine that an abnormality has occurred, and unless the abnormality is resolved, the teaching signal for the mechanical device will not be validated no matter how the deadman switch is operated thereafter. Thereby, the occurrence of a single failure occurring in the teaching pendant can be detected quickly, and the safety of the operator can be ensured more reliably.
[0047]
(2) When the output state of the plurality of enable signals based on the ON / OFF states of the plurality of main contacts according to the operation state of the deadman switch does not coincide with each other for a predetermined time or more, an abnormality has occurred in the deadman switch. By judging, it is possible to accurately detect contact welding occurring at one of the main contacts of the deadman switch after a predetermined time has elapsed, and teaching work for the mechanical device can be performed in a state where welding has occurred at one main contact. It can be reliably prevented from continuing.
[0048]
(3) When the discriminating means detects a mismatch between the output states of the plurality of enable signals, the time counting means for timing a predetermined time is activated, and when the time measuring means is timed up, the abnormality notifying means generates an abnormality in the teaching pendant. , It is possible to quickly detect the occurrence of a single failure in the teaching pendant with a simple configuration including the discrimination means, the timing means, and the abnormality notification means.
[0049]
In this way, it is possible to quickly detect the occurrence of welding of the main contact of the deadman switch, which is a single failure, before the next teaching operation, and by causing the operator to recognize this state, the teaching pendant causing the failure It is possible to prevent the teaching work from being continued by using and to ensure the safety of the worker more reliably.
[Brief description of the drawings]
FIG. 1 is a front view and a rear view of a teaching pendant to which a safety device according to an embodiment of the present invention is applied.
FIG. 2 is a circuit diagram showing a configuration of the safety device.
FIG. 3 is a circuit diagram of an enable device built in the teaching pendant.
FIG. 4 is a circuit diagram of the enable device when one deadman switch is operated to a second position.
FIG. 5 is a circuit diagram of the enable device when one deadman switch is operated to the second position and the other deadman switch is operated to the third position.
FIG. 6 is a circuit diagram of the enable device when one deadman switch is operated to the second position and the other deadman switch is returned from the third position to the first position.
FIG. 7 is a circuit diagram of the enable device when contact welding is generated at one main contact in one deadman switch operated up to a second position.
FIG. 8 is a circuit diagram of the enable device in a state in which both deadman switches have returned to the first position in a state where contact welding has occurred at one main contact in one deadman switch.
FIG. 9 is a circuit diagram of the enable device when contact welding is generated at both main contacts in one deadman switch.
[Explanation of symbols]
10-Teach pendant
20-Safety circuit
21-EX-OR circuit (discriminating means)
22-Timer circuit (time measuring means)
23-alarm circuit (notification means)
100-enable device
101a, 101b-deadman switch
120-Safety relay module
C1-first enable signal circuit
C2-second enable signal circuit

Claims (3)

Select an enable signal for enabling the teaching signal for the mechanical device according to the operating state of the deadman switch, which is in the first OFF state during non-operation, the ON state during intermediate operation, and the second OFF state during complete operation. Used for teaching pendants with multiple enable signal circuits to output,
Determining means for determining whether or not all output states of the plurality of enable signals from the plurality of enable signal circuits match each other;
A timing unit that starts when the discriminating unit detects a mismatch in the output states of the plurality of enable signals and starts timing, and resets when the discrepancy in the output state is no longer detected;
An abnormality notifying means for notifying the occurrence of an abnormality in the teaching pendant when the time measuring means is timed up according to a predetermined time set in advance;
The safety device of the teaching pendant, characterized in that provided. The deadman switch includes a plurality of main contacts that are turned off in a non-operation state and a complete operation state and turned on in an intermediate operation state,
The teaching pendant safety device according to claim 1, wherein each of the plurality of enable signal circuits includes one main contact of the deadman switch. Each of the deadman switches includes a plurality of main contacts,
  The predetermined time is a sufficiently short time to satisfy that the time is longer than the error time of the operation timing of the plurality of main contacts.
  3. The teaching pendant safety device according to claim 2.

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