JP6529878B2 - Control system - Google Patents

Description

  The present invention relates to a control system including a robot control device that controls a welding robot and a wire feeding control device that controls a wire feeding device.

  DESCRIPTION OF RELATED ART Conventionally, what provided the wire feeding apparatus which feeds a welding wire is known in a welding robot (for example, refer patent document 1).

Japanese Patent Application Publication No. 2003-311413

  It has been practiced to supply power to such a welding robot wire feeding device separately from the robot's drive system. In that case, power sources are required for the welding robot and the wire feeding device, respectively, and the scale of the device is correspondingly increased.

  The present invention has been made to solve the above problems, and a control system comprising a robot control unit for controlling a welding robot and a wire feed control unit for controlling a wire feeding unit To reduce the size of the circuit that supplies the power for the

In order to achieve the above object, a control system according to the present invention comprises a robot control device for controlling a welding robot, and a wire feeding control device for controlling a wire feeding device for feeding welding wires in a welding robot. The robot control apparatus performs servo control of a drive motor of each axis of the welding robot according to control of each axis position by the control unit and a control unit that performs control on each axis position of the welding robot. The servo controller includes a controller and a stop unit for stopping servo control according to control by the control unit, and the servo controller converts a switch that is opened and closed by the stop unit, alternating current from the power supply into direct current, and Welding according to the power from the rectifying circuit for supplying to the wire feed control device, the smoothing capacitor provided at the rear stage of the switch, and the smoothing capacitor Comprising a motor driver for operating the driving motor of each axis of the bot, a servo control unit for controlling the motor driver in accordance with the control by the control unit, and is intended.
With such a configuration, the power supplied to the wire feeding device can be supplied from the robot control device that controls the welding robot, and thus there is no need to separately provide a power supply circuit for wire feeding. As a result, the circuit size can be reduced compared to the case where a separate power supply for the wire feeding device is provided. Also, by taking the power supplied to the wire feed control device from the node at the front of the switch in the servo controller, even if the power supply of the servo controller is turned off, the wire feed device can It will be able to operate. As a result, for example, even when the servo controller is off, such as at the time of system setup, the movement of the welding wire by the wire feeding device becomes possible.

Further, in the control system according to the present invention, the rectifier circuit may include a capacitor, and the capacity of the smoothing capacitor may be smaller than the capacity of the capacitor included in the rectifier circuit.
Such a configuration can prevent a large current from flowing in the switch when the switch is turned on. As a result, when the switch is turned on, the occurrence of arcing in the switch can be suppressed.

Further, in the control system according to the present invention, the wire feed control device has a motor driver for operating the feed motor of the wire feed device according to the power from the rectifier circuit, and the servo control unit The motor driver of the feed control device may also be controlled.
With such a configuration, the configuration of the wire feeding control device can be simplified, and the circuit scale of the control system as a whole can be reduced.

  According to the control system according to the present invention, since the power supplied to the feed motor of the wire feeding device can be supplied from the robot control device that controls the welding robot, the circuit scale can be reduced.

Block diagram showing the configuration of the control system according to the embodiment of the present invention Block diagram showing the configuration of the servo controller in the same embodiment Block diagram showing the configuration of the wire feeding control device in the embodiment Block diagram showing another configuration of the control system according to the same embodiment Block diagram showing another configuration of the servo controller in the same embodiment Block diagram showing another configuration of the wire feeding control device in the embodiment

  Hereinafter, a control system according to the present invention will be described using an embodiment. In the following embodiments, the components denoted by the same reference numerals are the same or correspond to each other, and the description thereof may not be repeated. The control system according to the present embodiment supplies power to the wire feeding control device from a servo controller of the robot control device.

FIG. 1 is a block diagram showing the configuration of the control system 1 according to the present embodiment, FIG. 2 is a block diagram showing the configuration of the servo controller 12, and FIG. 3 shows the configuration of the wire feed control device 20. It is a block diagram shown.
The control system 1 according to the present embodiment includes a robot control device 10 that controls the welding robot 2 and transmits an instruction regarding welding to the welding power source 3 and a wire feeding control device 20 that controls the wire feeding device 4. .

  The welding robot 2 is an industrial robot used to perform welding, and has a plurality of arms connected by joints driven by a drive motor via a reduction gear. The drive motor has an encoder, which detects the current position of the drive motor. In addition, a welding torch that performs arc welding on a base material (workpiece) is attached to the tip of the manipulator of the welding robot 2. Then, a welding wire is fed from the wire feeding device 4, and a high voltage is applied between the welding wire at the tip of the welding torch and the base material by the welding power source 3 to generate an arc. The welding of the base material is performed by melting the welding wire and the base material by heat. The drive motor of each axis of the welding robot 2 is controlled by the robot control device 10. The configuration of welding robot 2 is already known, and the detailed description thereof will be omitted.

  The welding power source 3 supplies a high voltage used in welding to the welding torch or the base material in accordance with an instruction or the like transmitted from the robot control device 10. Further, the welding power source 3 transmits an instruction regarding the feeding of the welding wire to the wire feeding control device 20. In addition, the structure of the welding power supply 3 is already well-known, and the detailed description is abbreviate | omitted.

  The wire feeding device 4 feeds the welding wire to the welding torch of the welding robot 2. The feed may be a pull method, a push method, or both. The feed motor has an encoder by which the current position of the feed motor is detected. The wire feeding device 4 may or may not be provided, for example, on a part of the manipulator of the welding robot 2. The wire feeding device 4 may or may not be, for example, rapidly repeating advancing (inching) and retracting (retracting) the welding wire with respect to the base material. The feed motor of the wire feeder 4 is controlled by the wire feed controller 20. The configuration of the wire feeding device 4 is already known, and the detailed description thereof will be omitted.

  The robot control device 10 includes a control unit 11, a servo controller 12, and a stop unit 13.

  The control unit 11 performs control regarding each axis position of the welding robot 2. That is, the control unit 11 controls the drive motor of each axis of the welding robot 2. The control is performed by outputting the position command value of each axis of the welding robot 2 to the servo controller 12 according to the teaching information stored in the recording medium (not shown) and the operation signal inputted from the teaching pendant (not shown). It may be. By the control, the welding torch of the welding robot 2 is moved to a desired position. Moreover, the control part 11 also performs control regarding welding. The control transmits the start and end of welding, the output voltage, the start and end of feeding of the welding wire, etc. to the welding power source 3 according to a welding operation program and welding conditions stored in a recording medium (not shown). It may be In addition, the control unit 11 may output an instruction to cause the welding robot 2 to stop in an emergency to the stopping unit 13 when an abnormality occurs, or may send an instruction to stop the welding power supply 3 to the welding power supply 3.

  The servo controller 12 performs servo control of the drive motor of each axis of the welding robot 2 according to the control of each axis position by the control unit 11. As shown in FIG. 2, the servo controller 12 includes a rectifier circuit 31, a switch 32, a smoothing capacitor 33, an encoder circuit 34, a servo control unit 35, a motor driver 36, and a regenerative discharge circuit 37. Prepare.

  The rectifier circuit 31 converts alternating current from the power supply 5 into direct current, and supplies the direct current to the switch 32 and the wire feed control device 20. The power supply 5 may be a three-phase alternating current power supply. The rectifying circuit 31 may smooth the pulsating current after the rectification. In the present embodiment, the case where the rectifier circuit 31 has a capacitor for smoothing is mainly described. The electric power supplied from the rectifying circuit 31 is used for the operation of the welding robot 2 and the motor of the wire feeding device 4. Therefore, the electric power supplied from the rectifier circuit 31 to the wire feeding control device 20 is used to operate the feeding motor of the wire feeding device 4. Further, configurations other than the motor, for example, the control unit 11 and the servo control unit 35 operate with power of a system different from the power supplied from the rectifier circuit 31.

  The switch 32 switches the supply of DC power from the rectifier circuit 31 to the smoothing capacitor 33. That is, when the switch 32 is on, DC power is supplied to the smoothing capacitor 33, and when the switch 32 is off, DC power is not supplied to the smoothing capacitor 33. The opening and closing of the switch 32 is controlled by the stop unit 13. The switch 32 may be, for example, a magnet switch (electromagnetic switch) or a relay (relay). The switch 32 is a two-pole switch for switching direct current.

  The smoothing capacitor 33 is provided downstream of the switch 32. When the switch 32 is on, the DC power from the rectifier circuit 31 is supplied. The capacity of the smoothing capacitor 33 may be smaller than the capacity of the capacitor of the rectifying circuit 31. In the conventional servo controller, the switch is present outside the servo controller. In that case, when the switch is turned on, inrush current will flow to the rectifier circuit, and arc discharge may occur in the switch. On the other hand, as shown in FIG. 2, when the switch 32 is located in the latter stage of the rectifier circuit 31 and the capacity of the smoothing capacitor 33 is smaller than the capacity of the capacitor of the rectifier circuit 31, the switch 32 is Since the inrush current at the time of turning on becomes smaller than before, the arc discharge generated in the switch 32 can be weakened. As a result, wear of the contacts of the switch 32 can be reduced.

  The encoder circuit 34 receives the current position of the drive motor of each axis of the welding robot 2 from the encoder and passes it to the servo control unit 35. The encoder circuit 34 may also receive the speed of the drive motor of each axis and pass it to the servo control unit 35. The encoder circuit 34 may be, for example, a gate array that outputs the current position or the like received in parallel to the bus of the servo control unit 35. If the servo control unit 35 can directly receive the current position or the like, the servo controller 12 may not have the encoder circuit 34.

  The servo control unit 35 controls the motor driver 36 according to the control by the control unit 11. Specifically, the servo control unit 35 receives the position command value of each axis from the control unit 11, receives the current position of each axis from the encoder circuit 34, and the like, and uses them for each of the welding robots 2 Feedback control is performed such that the current position of the drive motor is at the position indicated by the position command value. The servo control unit 35 may perform PWM control on the motor driver 36 according to the current command value calculated by feedback control using the position command value, the current position, and the like.

  The motor driver 36 is controlled by the servo control unit 35, and operates the drive motor of each axis of the welding robot 2 in accordance with the power from the smoothing capacitor 33. The motor driver 36 may be an inverter circuit. Specifically, the motor driver 36 has an IGBT (Insulated Gate Bipolar Transistor) bridge and a current detection circuit, and according to the PWM control by the servo control unit 35, the drive motor of each axis is converted to the current command value. A corresponding current may be supplied. The current current detected by the current detection circuit may be used in feedback control in the servo control unit 35.

  The regenerative discharge circuit 37 absorbs generated power generated when the drive motor of each axis of the welding robot 2 decelerates. The generation of overvoltage can be prevented by the regenerative discharge circuit 37. The smoothing capacitor 33 and the regenerative discharge circuit 37 are disposed downstream of the switch 32 in consideration of the back electromotive force due to the inductance of the motor when the servo is off.

  The stop unit 13 stops servo control in the servo controller 12 according to control by the control unit 11. The stop unit 13 turns off the switch 32 when stopping servo control, and turns on the switch 32 when operating servo control. Further, the stop unit 13 may stop the servo control according to the control other than the control by the control unit 11. For example, servo control may be stopped in response to a signal from an emergency button of a teach pendant, opening and closing of a door of a safety fence, a safety plug provided on a safety fence, a mat switch or the like. Since the stop of the servo control is performed by turning off the switch 32, in the servo controller 12, the rectifier circuit 31 which is present before the switch 32 operates regardless of the stop of the servo control. Become.

  The respective components of the control unit 11 and the stop unit 13 of the robot control device 10, and the respective configurations of the encoder circuit 34 and the servo control unit 35 of the servo controller 12, the motor driver 36, the regenerative discharge circuit 37, etc. It is the same as the control device, and the detailed description thereof is omitted.

  The wire feeding control device 20 controls the feeding of welding wires to the welding robot 2 by the wire feeding device 4, and as shown in FIG. 3, the encoder circuit 21, the servo control unit 22, and the motor And a driver 23.

  The encoder circuit 21 receives the current position or the like of the feed motor of the wire feeding device 4 from the encoder of the feed motor, and passes it to the servo control unit 22. The encoder circuit 21 is the same as the encoder circuit 34 of the servo controller 12, and the detailed description thereof is omitted.

  The servo control unit 22 controls the motor driver 23 according to the control by the welding power source 3. Specifically, the servo control unit 22 receives an instruction on the feeding of the welding wire from the welding power source 3, receives the current position of the feeding motor from the encoder circuit 21 and the like, and uses them. The feedback control is performed so that the feeding speed of the welding wire by 4 becomes the one according to the instruction. The servo control unit 22 may perform PWM control on the motor driver 23 according to the current command value calculated by the feedback control using the instruction regarding the feeding of the welding wire and the current position or the like.

  The motor driver 23 is controlled by the servo control unit 22 and operates the feeding motor of the wire feeding device 4 according to the power from the rectifying circuit 31 of the servo controller 12. The motor driver 23 may be an inverter circuit. Specifically, the motor driver 23 has an IGBT bridge and a current detection circuit, and supplies a current according to the current command value to the feed motor according to the PWM control by the servo control unit 22. It may be. The current current detected by the current detection circuit may be used in feedback control in the servo control unit 22. Thus, the feed motor of the wire feeding device 4 is operated by the power supplied from the rectifier circuit 31 of the servo controller 12. On the other hand, it is assumed that the configuration other than the feed motor, for example, the servo control unit 22 operates with the power of the system different from the power supplied from the rectifier circuit 31.

  The servo controller 12 of the robot control device 10 may have a motor driver for an external shaft different from the drive motor of the welding robot 2. In that case, the motor driver for the external shaft may be used as the motor driver 23 of the wire feeding control device 20. When the motor driver for the external shaft is used as the motor driver 23, the robot control device 10 and the wire feeding control device 20 are integrally configured, and the portion having the function of controlling the welding robot 2 is robot control. It may be considered that the wire feeding control device 20 is the device 10 and a place having a function of controlling the wire feeding device 4. The external shaft is, for example, a movable jig (for example, a positioner, a turntable, etc.) interlocked with the welding robot 2.

  Further, each component in the wire feed control device 20 is the same as the conventional wire feed control device except that the motor driver 23 receives the supply of electric power from the servo controller 12, and thus the detailed description thereof is omitted. Do.

  In addition, since the feed motor of the wire feed device 4 has a small capacity compared to the drive motor of each axis of the welding robot 2, the wire feed control device 20 has no smoothing capacitor or regenerative discharge circuit. May be

  Here, the supply of power to the feed motor of the wire feed device 4 will be described. As shown in FIG. 2, power is supplied to the wire feeding control device 20 from the front stage of the switch 32, and the power is supplied to the feeding motor of the wire feeding device 4. Power is supplied to the feed motor of the wire feeder 4 regardless of whether it is turned off. Therefore, even when the welding robot 2 is in the servo-off state, the welding wire can be fed. The welding wire may be fed, for example, by operating a teach pendant, a feeding switch provided in the wire feeding device 4 or the like. Note that, for example, the feed instruction of the welding wire input from the teaching pendant may be input to the servo control unit 22 of the wire feed control device 20 via the control unit 11 and the welding power source 3. Further, for example, the welding wire feeding instruction input in the wire feeding device 4 may be input to the servo control unit 22 of the wire feeding control device 20 via a path (not shown). Thus, for example, when setting up the system, if you want to feed the welding wire of pack wire or reel wire to the tip of the welding torch, or when replacing or removing the system, up to the tip of the welding torch When it is desired to recover the welding wire that has reached it, or when it is desired to move the welding wire at the time of welding the wire, the wire feeding device 4 can be operated even in the servo-off state.

  As described above, according to the control system 1 according to the present embodiment, electric power can be supplied from the robot control device 10 to the wire feeding device 4 via the wire feeding control device 20. Therefore, for feeding the welding wire There is no need to provide a separate power supply. Further, in the supply of power from the robot control device 10 to the wire feeding control device 20, the rectified DC power is supplied to the wire feeding control device 20 from the front stage of the switch 32 controlled by the stopping unit 13. As a result, the wire feeding device 4 can be operated even in the state in which the switch 32 is turned off by the stopping unit 13, that is, in the state of the servo off. In addition, the conventional servo controller does not have a switch, and the switch controlled by the stopping unit 13 turns on / off the power of the entire servo controller. In such a case, even if power from the rectifier circuit of the servo controller is supplied to the wire feed control device 20, such as when starting up, replacing, or removing the system, or welding the welding wire, etc. In the situation where the servo controller is turned off, the power supply to the feed motor of the wire feeding device 4 is also turned off, so that it was not possible to move the welding wire. On the other hand, in the present embodiment, such a disadvantage can be avoided. Also, as in the conventional switch, when it was necessary to switch on and off the entire servo controller, it was necessary to use a three-pole switch. However, the switch 32 in this embodiment is a power supply after rectification. In order to turn on and off, two poles will be sufficient. Further, since the capacity of the smoothing capacitor can be divided into the front stage (rectification circuit 31) and the rear stage (smoothing capacitor 33) of the switch 32, rush power can be reduced. As a result, the switch 32 Can also be miniaturized.

  In the above description, although the case where the wire feed control device 20 includes the encoder circuit 21 and the servo control unit 22 has been described, this may not be the case. The processing of the encoder circuit 21 and the servo control unit 22 included in the wire feed control device 20 may be performed by the encoder circuit 34 and the servo control unit 35 in the servo controller 12. In that case, the configuration of the control system 1 is as shown in FIG. 4, the configuration of the servo controller 12 of the robot control device 10 is as shown in FIG. 5, and the configuration of the wire feeding control device 20 Becomes as shown in FIG. In FIGS. 4 to 6, the welding power source 3 transmits an instruction relating to the supply of welding wire to the servo controller 12 of the robot control device 10 instead of transmitting the instruction to the wire supply control device 20. The instruction regarding the feeding of the welding wire will be received by the servo control unit 35. Further, the current position or the like acquired by the encoder of the feed motor of the wire feeding device 4 is received by the encoder circuit 34 in the servo controller 12 of the robot control device 10. The servo control unit 35 also controls the motor driver 23 of the wire feed control device 20. Specifically, the servo control unit 35 controls the wire feeding control device 20 based on the instruction regarding the feeding of the welding wire received from the welding power source 3 and the current position of the feeding motor received from the encoder circuit 34. Control of the motor driver 23 is performed. The current current detected by the current detection circuit of the motor driver 23 may be passed to the servo control unit 35 and used in feedback control. By doing this, the processing of the encoder circuit 21 and the servo control unit 22 of the wire feed control device 20 can be executed by the encoder circuit 34 and the servo control unit 35 in the servo controller 12 of the robot control device 10 become. As a result, the circuit of the servo amplifier of the welding robot 2 can be utilized to the maximum extent, and the wire feed control device 20 does not have to have its own servo control unit. The configuration can be simplified. The servo controller 12 of the robot control device 10 may also be able to control an external axis other than the drive motor of the welding robot 2. In that case, the function for the external shaft may be used for servo control for the wire feed control device 20.

  Moreover, although the case where each motor of the welding robot 2 and the wire feeding apparatus 4 was an AC servomotor was demonstrated in the said description, the feed motor of the wire feeding apparatus 4 may be a DC motor. In that case, the motor driver 23 is preferably a motor driver for a DC motor.

Further, in the servo controller 12 in the present embodiment, a brake circuit may be connected to the servo control unit 35, and when a certain condition is satisfied, control may be performed to apply a brake to the motor.
Moreover, although the case where the encoder acquires the current position and the like of each motor has been described in the present embodiment, the current position and the like may be acquired using other means such as a resolver.

  Also, in the above embodiment, each processing or each function may be realized by centralized processing by a single device or a single system, or distributed processing by a plurality of devices or a plurality of systems. It may be realized by

  Further, in the above embodiment, the transfer of information performed between the components is performed by, for example, one of the components if the two components performing the transfer of information are physically different. It may be performed by the output of the information and the reception of the information by the other component, or if the two components that exchange the information are physically the same, one of the components It may be performed by moving from the phase of processing corresponding to to the phase of processing corresponding to the other component.

  Further, in the above embodiment, when two or more components included in each device have a communication device, an input device, etc., the two or more components may physically have a single device. Alternatively, they may have separate devices.

  Further, in the above embodiment, each component may be configured by dedicated hardware, or a component that can be realized by software may be realized by executing a program.

  Further, it is needless to say that the present invention is not limited to the above embodiments, and various modifications are possible, which are also included in the scope of the present invention.

  As mentioned above, according to the control system by this invention, the power supply for wire feeding can be supplied from the robot control apparatus which controls a welding robot, and it is useful as a system etc. which control a welding robot and a wire feeding apparatus.

Reference Signs List 1 control system 2 welding robot 3 welding power supply 4 wire feeding device 5 power supply 10 robot control device 11 control unit 12 servo controller 13 stop unit 20 wire feeding control device 21 34 encoder circuit 22 35 servo control unit 23 36 motor Driver 31 Rectifier circuit 32 Switch 33 Smoothing capacitor 37 Regenerative discharge circuit

Claims (3)

A control system comprising: a robot control device for controlling a welding robot; and a wire feeding control device for controlling a wire feeding device for feeding welding wires in the welding robot,
The robot controller
A control unit that performs control on each axis position of the welding robot;
A servo controller that performs servo control of a drive motor of each axis of the welding robot according to control of each axis position by the control unit;
And a stop unit configured to stop the servo control according to control by the control unit.
The servo controller is
A switch that is opened and closed by the stop unit;
A rectifier circuit that converts alternating current from a power source into direct current and supplies the direct current to the switch and the wire feed control device;
A smoothing capacitor provided downstream of the switch;
And a motor driver for operating more drive motors for each axis of the welding robot in the power supplied via the smoothing capacitor from the rectifier circuit,
A control system comprising: a servo control unit which controls the motor driver according to control by the control unit. The rectifier circuit comprises a capacitor,
The control system according to claim 1, wherein a capacity of the smoothing capacitor is smaller than a capacity of a capacitor included in the rectifier circuit. The wire feed control device has a motor driver for operating the more feed motor of the wire feeder to the power from the rectifier circuit,
The control system according to claim 1, wherein the servo control unit also controls a motor driver of the wire feeding control device.

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