JP2008178934A - Robot controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically add a teaching point to a corresponding position or correct its position even without moving another robot when performing edition operation on a working line of one robot such as addition of the teaching position or correction of its position. <P>SOLUTION: In a robot controller for storing a plurality of working lines formed at a plurality of teaching points taught for each of the same number of robots in one work program, when a teaching point is added or its position is corrected as edition operation for any one of the working lines WR1, a ratio between a spacing distance (a) between the teaching point P111 subjected to edition operation and an immediately previous teaching point P110 and a spacing distance b between the teaching point P111 subjected to edition operation and an immediately subsequent teaching point P120 is calculated, and a teaching point P220 corresponding to the teaching point P111 subjected to edition operation is added to the other working line WR2 or its position is corrected based on the ratio. As for arc-welding robots, for example, a fluctuation in welding speed between both robots can be inhibited. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a robot control apparatus that performs a machining operation by synchronously controlling a plurality of robots and a single external shaft (for example, a positioner).

  2. Description of the Related Art Conventionally, there has been known a robot control apparatus in which a plurality of robots simultaneously perform a machining operation on a plurality of machining positions of a workpiece installed on the positioner by synchronously controlling a plurality of robots and a single positioner. . For example, in the field of arc welding robots, welding of a plurality of welding locations of a workpiece installed on a positioner is simultaneously performed by two arc welding robots (see, for example, Patent Document 1).

  FIG. 7 is a block diagram of an arc welding robot system that uses two arc welding robots (hereinafter simply referred to as robots) and a robot controller that synchronously controls one positioner.

  In the figure, a robot R 1, a robot R 2, and a positioner P (hereinafter collectively referred to as a control target) are connected to a robot control device 1. The positioner P is provided with a workpiece W having a work line WR1 and a work line WR2 which are welding locations. The workpiece W can take an optimum welding posture with respect to the robot R1 and the robot R2 by controlling the rotation of the positioner P. The operator teaches a plurality of teaching points by a method described later so that each of the robot R1 and the robot R2 moves along the work line WR1 and the work line WR2. The work line WR1 and the work line WR2 are substantially bilaterally symmetric.

  The robot R1 and the robot R2 automatically perform arc welding on the workpiece W, and are each constituted by a plurality of arms and a plurality of servo motors (not shown) for rotationally driving them. . An arc welding torch (not shown) is attached to the tip of the arm.

  The robot control device 1 is for controlling a control target. The main control unit 3 serving as the center of the robot control device 1, an operation control unit 11 that performs a trajectory calculation of each control target, and a drive command to the servo motor of each control target. A drive command unit 12 is provided, a teach pendant interface 2 for connecting the teach pendant TP, and a work program storage unit 4 for storing a work program.

  The teach pendant TP is a portable teaching operation panel, and is connected to the teach pendant interface 2 of the robot control device 1. The teach pendant TP includes a control object selection switch for selecting a control object to be manually operated, an axis operation key for actually moving each control object by manual operation, and the like (none of which are shown). By operating these switches, keys, etc., the control object can be moved to a desired position, and the position can be stored in the work program 5 as a teaching point. Also, editing operations such as adding a new teaching point to the created work program 5 and correcting the position of the stored teaching point are possible. Further, the teach pendant TP is also provided with a display unit, which displays the teaching contents stored in the work program 5, various dialog messages to the operator, and the like. The work program storage unit 4 is a nonvolatile memory for storing the work program 5.

  The activation box SB is for inputting an activation signal for performing a reproduction operation of the created work program 5 to the robot control device 1.

  Next, teaching for synchronously controlling two robots and one positioner will be described using the work program 5 as an example.

  In the illustrated work program 5, the point PT indicates the number of the teaching point, and starts from 001 and is incremented by one every time the teaching point is stored. The command CM is a movement command for moving to the teaching point. For example, if it is a MOVE command, a PTP operation is performed on the teaching point, and if it is a LINE command, a linear interpolation operation is performed on the teaching point. Note that the command CM can teach various types of commands such as a command to start welding and a command to input / output a signal to / from an external device in addition to the movement command described above. 5 shows an example in which only a movement command is taught for convenience of explanation. A position PR1 indicates a teaching point (P110 to P150, etc.) of the robot R1, and a position PR2 indicates a teaching point (P210-P250, etc.) of the robot R2. The actual position data of each teaching point should be expressed by coordinate values in the work coordinate system, which is an orthogonal coordinate system based on the positioner P. Here, for convenience of explanation, each teaching point Point position data is expressed in a format such as P110.

  Next, an example in which the teaching pendant TP is operated to teach the teaching point to be controlled will be described. If the work line WR1 and the work line WR2 are bilaterally symmetric, the distance between the teaching points (welding length) taught by the operator needs to be the same on the left and right. However, as long as the operator manually moves the control target, it is technically difficult to make the distance between the teaching points (welding length) completely the same. Therefore, in general, one robot (for example, the robot R1) is first taught, and then the other robot (for example, the other robot (for example, the robot R1) is subjected to a symmetric shift for processing the position data of the teaching points so as to be symmetrical. The teaching point of the robot R2) is automatically calculated. That is, the distance between the teaching points (welding length) can be made the same on the left and right by performing the symmetric shift. In the following, the teaching when using a symmetric shift will be described. Therefore, the distance between the teaching points (welding length) is finally the same on the left and right.

  The positioner P and the robot R1 are moved to a position (that is, a welding start point) as a point 001. Specifically, first, the positioner P is selected as a target for manual operation and moved to the welding start point. Next, the robot R1 is selected as a manual operation target and moved to a position where the position and orientation with respect to the positioner P are optimal. Since the robot R2 automatically calculates the teaching point by the symmetrical shift, it is not necessary to move at this stage.

  Next, the movement command up to this point 001 is selected. Here, it is assumed that the MOVE instruction is selected. Then, a storage operation for storing the command is performed. At this time, P110 is stored as the teaching point of the robot R1, and P210 is stored as the teaching point of the robot R2. Dummy data is stored in the teaching point P210 of the robot R2 at this time. Thus, the teaching points of both the robot R1 and the robot R2 are stored by one movement command.

  The above procedure is repeated to teach necessary teaching points along the work line WR1.

  When the teaching of the positioner P and the robot R1, that is, the teaching of the work line WR1, is completed, a symmetric shift is performed. As a result, the teaching point of the robot R2 is automatically calculated and stored. In other words, the position data of the robot R2 stored as dummy data is changed to position data obtained by converting the position data of the robot R1 symmetrically.

  When the symmetrical shift is completed, the work line WR1 is completed at a plurality of teaching points (P110 to P150, etc.) of the robot R1, and the work line WR2 is completed at a plurality of teaching points (P210 to P250, etc.) of the robot R2. That is, a plurality of work lines are stored in one work program 5. Further, since the teaching points of both the robot R1 and the robot R2 are taught by one movement command, the number of teaching points forming the work line WR1 and the work line WR2 is the same.

  When an activation signal is input from the activation box SB to perform the reproduction operation of the created work program 5, the main control unit 3 interprets the command CM based on the work program 5, and the operation control unit 11 performs a trajectory calculation. The drive command unit 12 outputs an operation control signal to each servo motor to be controlled, and rotationally drives the corresponding shaft. The main control unit 3 outputs a welding control signal to a welding power source (not shown) at a predetermined timing, and a voltage is applied between the arc welding torch (not shown) and the workpiece W. As a result, the robot R1 and the robot R2 perform welding work on the workpiece W while simultaneously reaching the teaching points of the work line WR1 and work line WR2.

  When a part of the work line has a left-right asymmetric part, the reproduction operation is performed after performing an editing operation such as addition of a teaching point and correction of the position of the teaching point after performing a symmetric shift. The same editing operation is performed when there is a problem in the teaching result as a result of the reproduction operation. However, the above-described prior art has problems to be described later when performing an editing operation.

Japanese Patent Laid-Open No. 10-24369

  FIG. 8 is a diagram illustrating an example in which a teaching point is added to a taught work line. FIG. 6A shows a state before teaching points are added to the work line WR1 of the robot R1 and the work line WR2 of the robot R2. FIG. 7B shows a state after teaching points are added to FIG.

  In FIG. 5A, the work line WR1 is formed by teaching points P110 and P120. Similarly, the work line WR2 is formed by the teaching points P210 and P220.

  In FIG. 5B, P111 is a new teaching point to be added between the teaching points P110 and P120 of the work line WR1. When adding P111, the worker moves the robot R1 to the position of P111.

  Then, the robot R2 needs to be moved to the position P211 where the welding length is the same or the separation ratio between the front and rear teaching points is the same. That is, the separation ratio of the distance a between P110 and P111 and the distance b between P111 and P120 in the work line WR1 (a: b) needs to be P211 in the work line WR2. .

  However, since the robot R2 is moved by manual operation, it is impossible to make P211 completely coincide with the position where the separation ratio is (a: b). In most cases, for example, (a ': B'). Also, P211 may be taught at the same position as P210, forgetting to move the robot R2. Since the control is performed so that the teaching points are simultaneously reached during the reproduction operation, the difference in the welding speed between the robot R1 and the robot R2 increases as the difference in the separation ratio increases. For example, when the distance a ′ between P110 and P111 of the robot R1 is longer than the distance a ′ between P210 and P211 of the robot R2, the welding speed of the robot R2 is slower than the welding speed of the robot R1. Conversely, when the distance P 'between P110 and P111 of the robot R1 is shorter than the distance a' between P210 and P211 of the robot R2, the welding speed of the robot R2 becomes faster than the welding speed of the robot R1. That is, welding quality is adversely affected by differences in welding speed.

  In this way, when performing an editing operation such as adding a teaching point or correcting a position on the work line of one robot, the other robot is also positioned at a position where the welding length matches or the ratio of the separation distance from the preceding and following teaching points. It was necessary to move to the exact position where. If the other robot is not accurately moved to the corresponding position, the welding speed is different between both robots, which adversely affects the welding quality.

  Therefore, according to the present invention, when an editing operation such as addition of a teaching point or position correction is performed on the work line of one robot, the teaching point is automatically added to the corresponding position without moving the other robot. Alternatively, an object of the present invention is to provide a robot control device that prevents a difference in welding speed between both robots by correcting the position.

To achieve the above object, according to a first aspect of the present invention, a plurality of work lines formed by the same number of teaching points taught for each of a plurality of robots by a teach pendant are stored in one work program, and the plurality of robots In a robot control apparatus that performs a machining operation on a workpiece installed on an external axis while simultaneously reaching each teaching point of the work line,
When a teaching point, which is an editing operation for any one of the work lines, is added or corrected, the distance between the teaching point that has been edited and the immediately preceding teaching point, the teaching point that has been edited, and The ratio of the immediately following teaching point separation distance is calculated, and based on this ratio, the teaching point corresponding to the teaching point that has been edited is added or positioned with respect to a work line other than the working line that is being edited. A robot control apparatus including an automatic work line correction unit for correction.

  The second aspect of the present invention further includes a correction execution confirmation unit for displaying on the teach pendant and selecting whether or not to correct a work line other than the work line being edited, and when correction is selected, 2. The robot control apparatus according to claim 1, wherein when the corresponding teaching point is added or corrected, and no correction is selected, the corresponding teaching point is not added or corrected.

  According to the first invention, when an editing operation such as addition of a teaching point or position correction is performed on the work line of one robot, the corresponding position is automatically taught without moving the other robot. Since the point is added or the position is corrected, for example, in an arc welding robot, fluctuations in the welding speed between the two robots can be suppressed. As a result, the welding quality can be improved. Further, since it is not necessary to move the other robot, the teaching man-hour can be reduced.

  According to the second invention, since it is possible to select whether or not the correction result of one work line is reflected in the other work line, in addition to the effect of the first invention, for example, in an arc welding robot Can prevent the position from being automatically corrected when the operator is consciously teaching different welding lengths on both work lines.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on examples with reference to the drawings.

[Embodiment 1]
FIG. 1 is a block diagram of an arc welding robot system in which two robots and one positioner are synchronously controlled by the robot control apparatus according to the first embodiment of the present invention. 4 is different from FIG. 4 in that the main control unit 3 includes an automatic work line correction unit 7. Other configurations are the same as those shown in FIG.

  FIG. 2 is a flowchart showing a processing flow of the work line automatic correction unit 7. FIG. 3 is a diagram illustrating a state in which when a teaching point is added to one work line, a teaching point corresponding to the other work line is automatically added. More specifically, when a new teaching point P111 is added between the existing teaching points P110 and P120 of the robot R1 (work line WR1), between the teaching points P210 and P220 of the robot R2 (working line WR2). A state in which a teaching point P211 corresponding to is automatically added is shown.

  Below, based on these figures, the flow of processing of the work line automatic correction unit 7 will be described. Note that the addition or position correction as an editing operation on the work line can be easily determined by monitoring the key operation result of the teach pendant TP. In the following, the following processing will be described on the assumption that the teaching point P111 is added as an example.

  In step S1, when the teaching point P111 is added to the work line WR1, the separation distance a between the added teaching point P111 and the immediately preceding teaching point P110, and the separation between the added teaching point P111 and the immediately following teaching point P120. A ratio (a: b) to the distance b is calculated.

  In step S2, the position coordinate value between the teaching point P210 of the work line WR2 corresponding to the teaching point P110 and the teaching point P220 of the work line WR2 corresponding to the teaching point P120 is acquired, and the calculated ratio (a: b) is obtained. Based on this, the position of the teaching point P211 to be added to the work line WR2 is calculated.

  In step S3, the positions of the teaching point P111 and the corresponding teaching point P211 are stored.

  The case where the teaching point is added to one work line has been described above as an example, but the teaching point is automatically set to the other working line by the same method even when the position of the teaching point is corrected. The position can be corrected.

  As described above, when an editing operation such as adding a teaching point or correcting a position is performed on the work line of one robot, the teaching point is automatically added to the corresponding position without moving the other robot. Alternatively, since the position is corrected, for example, in an arc welding robot, fluctuations in the welding speed between the two robots can be suppressed. As a result, the welding quality can be improved. Further, since it is not necessary to move the other robot, the teaching man-hour can be reduced.

[Embodiment 2]
FIG. 4 is a block diagram of an arc welding robot system in which two robots and one positioner are synchronously controlled by the robot control apparatus according to the second embodiment of the present invention. In this figure, the difference from FIG. 1 is that the main control unit 3 is provided with a correction execution confirmation unit 8 for confirming whether or not a work line other than the work line whose position has been corrected is to be corrected, and a confirmation result. This is an automatic work line correction unit 7 that provides different correction results accordingly. Other configurations are the same as those shown in FIG.

  FIG. 5 is a flowchart for explaining the flow of processing of the correction execution confirmation unit 8. As in the first embodiment, the addition or position correction as an editing operation on the work line can be easily determined by monitoring the key operation result of the teach pendant TP. Below, the process of the correction execution confirmation part 8 is demonstrated as what performed addition operation of the teaching point P111 as an example.

  In step S1, a command signal for causing the teach pendant TP to display a message for confirming whether or not to correct a work line other than the work line whose position has been corrected as an editing operation is transmitted. The teach pendant TP displays a dialog message to that effect. The operator selects whether to modify or not according to the dialog message.

  In step S2, the selection result of “correct” or “not correct” selected by the operator is received. In step S 3, the reception result is transmitted to the work line automatic correction unit 7.

  FIG. 6 is a flowchart showing a processing flow of the work line automatic correction unit 7. In the figure, steps S2 to S4 are the same as steps S1 to S3 shown in FIG. Hereinafter, steps S1 and S5 different from FIG. 2 will be described.

  In step S1, the reply result from the correction execution confirmation unit 8 is confirmed. When “correct” is selected, the processing in steps S2 to S4 described in FIG. 2 is performed, and the corresponding teaching point is corrected in position. When “Do not modify” is selected, the process proceeds to step S5.

  In step S5, the position of the teaching point corresponding to the edited work line is corrected without correcting the position of the corresponding teaching point.

  As described above, since it is possible to select whether or not the correction result of one work line is reflected in the other work line, in addition to the effect of the first invention, for example, in an arc welding robot, both When the operator is consciously teaching different welding lengths on the work line, the position can be prevented from being automatically corrected.

  In the above embodiment, an example in which there are two work lines on the assumption that there are two arc welding robots is shown, but this embodiment is not limited to this. Even when there are three or more arc welding robots and there are three or more work lines, they remain when a teaching point is added or corrected for any one work line by the same method. It is possible to automatically add teaching points or correct the positions of the work lines.

1 is a block diagram of an arc welding robot system that synchronously controls two robots and one positioner by a robot control device according to a first embodiment of the present invention. FIG. It is a flowchart which shows the flow of a process of the work line correction execution part which concerns on 1st Embodiment of this invention. It is a figure which shows a mode that the teaching point corresponding to the other work line was automatically added when the teaching point was added to one work line by the work line correction execution part which concerns on 1st Embodiment of this invention. It is a block diagram of the arc welding robot system which controls synchronously two robots and one positioner with the robot controller concerning a 2nd embodiment of the present invention. It is a flowchart explaining the flow of a process of the correction execution confirmation part which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the flow of a process of the work line correction execution part which concerns on 2nd Embodiment of this invention. It is a block diagram of the arc welding robot system which controls synchronously two arc welding robots and one positioner with the conventional robot control apparatus. It is a figure which shows the example which adds a teaching point with respect to the work line already taught in the conventional robot control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot controller 2 Teach pendant interface 3 Main control part 4 Work program memory | storage part 5 Work program 7 Work line automatic correction part 8 Correction execution confirmation part 11 Operation control part 12 Drive command part a Separation distance b Separation distance P Positioner R1 Robot R2 Robot SB Start box TP Teach pendant W Work WR1 Work line WR2 Work line

Claims (2)

A plurality of work lines formed by the same number of teaching points taught for each of a plurality of robots by a teach pendant are stored in one work program, and the plurality of robots are externalized while simultaneously reaching each teaching point of the work lines. In a robot controller that performs machining operations on workpieces installed on axes,
When a teaching point, which is an editing operation for any one of the work lines, is added or corrected, the distance between the teaching point that has been edited and the immediately preceding teaching point, the teaching point that has been edited, and The ratio of the immediately following teaching point separation distance is calculated, and based on this ratio, the teaching point corresponding to the teaching point that has been edited is added or positioned with respect to a work line other than the working line that is being edited. A robot control device comprising an automatic work line correction unit for correction.   It further includes a correction execution confirmation unit that displays on the teach pendant whether or not to correct a work line other than the work line being edited, and adds a corresponding teaching point when correction is selected. The robot control apparatus according to claim 1, wherein when the position is corrected and not corrected is selected, the corresponding teaching point is not added or the position is not corrected.

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