JP2006082185A - Robot guiding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method wherein an operator safely directly operates a robot and corrects the position of the robot when a workpiece causes displacement in a play back operation. <P>SOLUTION: A direct operation device for guiding the robot is provided on a wrist tip end part of the robot, and the direct operation device is equipped with an enabling device which controls a permission state permitting the operation of the robot and a prohibition state prohibiting the operation of the robot. When the robot is stopped in a way during play back operation, the robot is made to be in the permission state by the operation of the enabling device, the guidance is performed, and made to be in the prohibition state after completion of positional correction. Afterward, the play back operation is continuously started based on the working program. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a robot guidance method in which an operator guides the robot as one work of a work program reproduction operation (playback operation) in a teaching playback type robot.

  In a robot, a work program in which work such as machining of a workpiece and its procedure is programmed is created and registered in the robot teaching mode, and the work program is reproduced in the robot reproduction mode to perform the intended work. . During the replay operation of the work program, the procedure is to isolate the robot from the worker with a safety fence, etc., so if there is a work position misalignment, etc., the regenerative operation cannot be continued or the robot There are problems that the workpiece becomes defective and the yield decreases, or the robot and the workpiece interfere or collide, and the workpiece or a tool attached to the robot is damaged. However, due to the processing accuracy of the workpiece and the displacement of the mounting position on the work table on which the workpiece is placed and fixed when working with a robot, the work program described above stably reduces the quality of many workpieces. It is necessary not to invite.

Therefore, a detector for detecting the displacement of the workpiece during the reproduction of the work program is provided, and the starting point of the work and the operation path of the robot are corrected or corrected based on the output of the detector. For example, the displacement of the welding start point of arc welding is moved toward the groove of the welded portion, the welding start point is detected by contact between the welding tip and the member to be welded, and arc discharge is generated. Control means is disclosed (for example, Patent Document 1).
In addition, a proposal has been made in which a workpiece is imaged by a camera, a feature point is detected from the image, a shift amount of the workpiece is calculated, and the workpiece is moved to a starting point (for example, Patent Document 2).
Further, there is disclosed a technique for changing the position of a teaching point based on input data when instruction data for changing the position of the robot is input from the input means during the reproduction of the work program (for example, Patent Document 3).
JP-A-9-10941 JP-A-5-213246 JP-A-10-301616

In the method of Patent Document 1 which is a conventional technique, if the amount of deviation of the starting point of the work increases, the amount of deviation is detected by the operation of the robot. For example, in arc welding applications, the amount of work deviation is small, such as detection of the arc start point.
Further, in the method of Patent Document 2, since an optical system is used for detection, illumination on the imaging surface and an optical path failure such as dust, dust, dirt, etc. will cause erroneous detection, and daily maintenance is important. This is a requirement, and there is a problem that the cost at the time of introduction increases.
Further, in the position correction of Patent Document 3, since the teaching point already taught is changed, it is effective when the amount of deviation is biased or when precise position correction is not required, for example, for painting applications. There is a problem that it cannot be applied when the position is different or in applications that require precise position correction.
The present invention has been made in view of such problems, and corrects a work position shift during regeneration operation by direct operation in which an operator safely guides the robot as one operation of regeneration operation. This eliminates the problem of misalignment by eliminating the restriction on the amount of displacement, precise correction by the operator, and low introduction costs, as well as flexibility in restoring the production line when an unexpected problem occurs around the robot. It is an object of the present invention to provide a method capable of providing

In order to solve the above problem, the present invention is as follows.
The invention according to claim 1 includes a robot and a direct operation device that guides the robot to a wrist tip of the robot, and controls the operation of the robot based on a work program registered in advance. In the robot guidance method of the robot system comprising the control device, the direct operation device includes an enable device that controls a permission state that permits the operation of the robot and a prohibition state that prohibits the operation of the robot, A first stage in which the robot stops in the middle of a replay operation based on a pre-registered work program; a second stage in which the robot is in the permitted state by operation of the enable device; and A third stage in which the robot is guided by operation, and the operation of the enable device. In those characterized a fourth step of the robot and the prohibited state, said robot comprising a fifth step of continuously start the reproduction operation based on the work program.
The invention according to claim 2 is characterized in that the stop in the middle of the reproduction operation of the first stage is a guidance command registered in advance in the work program.
The invention according to claim 3 is characterized in that the stop in the middle of the reproduction operation in the first stage is an incoming to an input device provided in the robot control device.
Further, the invention according to claim 4 is characterized in that the continuation of the reproduction operation based on the work program of the robot in the fifth stage is based on the absence of an operator in the vicinity of the robot as an activation condition. is there.

According to the present invention, the work start position on the work of the robot is corrected by the operator's direct operation, and then the work on the work is started. Therefore, the work position can be corrected by the operator. Can be eliminated, and the yield can be improved.
In addition, by installing an enable device like a direct operation device having an enable device, it is possible to ensure safety when the operator does not directly operate the robot even when the worker is close to the robot. .
In addition, the unmanned confirmation sensor automatically detects when an operator should not enter the safety fence, so if the operator should not enter the safety fence, the robot can be regenerated. By making an emergency stop, safety for the worker can be ensured.

  Hereinafter, specific examples of the method of the present invention will be described with reference to the drawings.

  FIG. 1 is a flowchart showing a processing procedure of a first robot guidance method embodying the present invention. FIG. 2 is a block diagram showing the configuration of the first robot system for carrying out the present invention. In FIG. 2, reference numeral 1 denotes a robot, which operates based on control of a robot controller (RC for short) 2. RC2 is equipped with an emergency stop switch (not shown), and when pressed in an emergency, the drive power to the robot 1 can be cut off and the operation of the robot 1 can be stopped. 3 is a teaching pendant (PP for short), which is used when creating a work program for the robot 1 and is equipped with a 3-position enabling device on the back and an emergency stop switch on the operation surface. The turning on and off of the device is controlled by an enable device. 4 is an operator and 5 is a work table on which a work is placed. Reference numeral 6 denotes a work on the work table 5, and 7 denotes a safety fence, which isolates the worker 4 from the robot 1 during the reproduction operation of the work program and ensures the safety of the worker 4 from the unexpected operation of the robot 1. . Reference numeral 8 denotes a direct operation device according to the embodiment of the present invention, and details will be described later. Reference numeral 9 denotes a restart button for the operation program reproduction operation after the direct operation. Further, the illustration of the entrance door for the worker 4 of the safety fence 7 is omitted.

FIG. 2A is a diagram for explaining a state during the regenerating operation of the work program, and FIG. 2B is a diagram for explaining an intervening state of the direct operation (robot guidance) during the regenerating operation. (c) is a figure explaining the state which restarts the reproduction | regeneration driving | operation of the work program after direct operation.
FIG. 3 is a block diagram showing the configuration of the direct operation device for carrying out the present invention. In the figure, reference numeral 10 denotes a robot tip, which shows the wrist tip of the robot 1 and is attached with a tool (not shown) for performing work. Reference numeral 11 denotes a gripper, which is gripped by the operator 4 during direct operation. Is a force sensor, which is attached to the robot tip 10 and to which the grip 11 is fixed, and 13 is a three-position enable device. Reference numeral 8 denotes a direct operation device, which includes a gripping unit 11, a force sensor 12, and an enable device 13.
The enable device 13 controls a permission state in which the operation of the robot 1 is permitted in the direct operation state and a prohibition state in which the operation of the robot is prohibited. Control is performed so that the operator 4 is permitted when the gripper 11 is gripped, and is prohibited when the gripper 11 is gripped and released.

The method of the present invention will be described step by step with reference to FIGS.
First, in step S101, the robot 1 is regeneratively operated, and preparations are made until immediately before direct operation. FIG. 2A shows the state of step S101, and the worker 4 is away from the robot 1 and is in a safe place.

  Next, in step S102, the robot 1 is temporarily stopped from regenerating, and the robot control system of RC2 is switched so that direct operation is possible. This switching is performed by executing a guidance command registered in the work program. This switching to the direct operation enabled state is also performed when a signal is input from an external device such as a higher-level production line control panel or when communication is input from an external device such as a higher-level production line control panel. There are various forms such as when a transmission signal is input from an external device, when a direct operation start button provided in RC2 or PP3 is pressed.

  Next, in step S103, the worker 4 enters the safety fence 7 and corrects the position of the robot 1 by using the direct operation device 8 provided at the tip of the wrist of the robot 1 as one operation of the regeneration operation. FIG. 2B shows the state of step S103.

  Next, in step S104, the worker 4 moves away from the robot 1 and presses the playback operation restart button 9 of the RC 2 outside the safety fence 7, thereby restarting the regeneration operation of the robot 1. The instruction to resume the work program for the regeneration operation is resumed immediately after the instruction stopped in step S102. FIG. 2C shows the state of step S <b> 104, and in FIG. 2C, the playback operation restart button 9 is equipped on RC <b> 2 outside the safety fence 7. However, the playback operation resuming button 9 can be separated as an external device by using the input function of RC2, etc., and can be installed at a location away from RC2.

FIG. 7A is an example of a work program including a guidance command, and FIG. 7B is an example of a trajectory of the tip of the robot when the present invention is implemented. In the figure, p1, p2, and p3 are taught points, which are referred to as a first teaching point, a second teaching point, and a third teaching point, respectively. Step S1 of the work program is a joint operation command with the target point as the first teaching point. Step S2 is a linear interpolation operation command with the target point as the second teaching point. Step S3 is a guidance command for switching the RC2 robot control of the present invention so that direct operation is possible. Step S4 is a linear interpolation operation command with the target point as the third teaching point.
From the second teaching point p2 to the point p2-1, the locus when the worker 4 holds the direct operating device 8 and guides the robot 1 is shown, and the step S4 of the work program is continued from the point p2-1. It shows that the linear interpolation operation with the target point as the third teaching point was performed.

  As described above, the operator 4 uses the direct operation device 8 to correct the work start position of the robot 1 on the workpiece 6, and the enable device 13 secures the safety of the worker 4 and corrects the position by direct operation before the workpiece. Since the work to 6 is resumed, the operator 4 can correct the workpiece position deviation with high accuracy, the workpiece position deviation can be eliminated, and the yield can be improved.

FIG. 4 is a flowchart showing a processing procedure of the second robot guidance method for carrying out the present invention.
First, in step S401, the robot 1 is regeneratively operated, and preparations until immediately before direct operation are made. FIG. 2A shows the state of step S401, where the worker 4 is away from the robot 1 and in a safe state.

Next, in step S402, the robot 1 is temporarily stopped from being regeneratively operated, the servo power is turned off, and the RC2 robot control system is switched so that direct operation is possible.
This switching is performed by executing a direct operation command registered in the work program. By turning off the servo power supply, it is possible to secure safety against the operator 4 approaching the robot 1.

  Next, in step S403, the worker 4 enters the safety fence 7 and lightly grips the grip portion 11 of the direct operation device 8 provided at the tip of the robot 1 together with the enable device 13, thereby turning on the servo power of the robot 1. Let The safety of the worker 4 is ensured by the enable device 13 held by the worker 4. FIG. 2B shows the state of step S403.

  Next, in step S404, the worker 4 in the safety fence 7 performs a direct operation of guiding the robot 1 with the direct operation device 8 as one operation of the regeneration operation, and corrects the position of the robot 1. The safety of the worker 4 is ensured by the enable device 13 held by the worker 4. FIG. 2B shows the state of step S404.

Next, in step S405, the worker 4 in the safety fence 7 releases the direct operation device 8 so that the enable device 13 is also opened, and the servo power supply of the robot 1 is turned off. The safety of the worker 4 is ensured by turning off the servo power. FIG. 2B shows the state of step S405.
Note that steps S403 to S405 may be repeated in order to directly operate the robot 1 at a desired position.

  Next, in step S406, the operator 4 departs from the robot 1 and presses the playback operation resumption button 9 outside the safety fence 7, whereby the RC 2 turns on the servo power and resumes the reproduction operation of the robot 1. The instruction to resume the work program for the regeneration operation is resumed immediately after the instruction stopped in step S402.

  As an outline of the operation of the direct operation device 8, when the RC 2 is controlled for direct operation, the operator 4 grasps the grip portion 11 and the enable device 13 and works by manually applying force in a desired direction. The direct operation is realized by transmitting the force of the person 4 to the force sensor 12 through the grip portion 11. The role of the enabling device 13 is to stop the operation of the robot 1 by cutting off the servo power if the operator 4 does not hold the gripping part 11 and the enabling device 13 when the RC 2 is in control for direct operation. When the operator 4 grasps the grip 11 and the enable device 13 lightly, the servo power is turned on to enable direct operation. When the operator 4 grasps the grip 11 and the enable device 13 more strongly, the servo power is shut off and the robot 1 is turned off. Stop operation.

In this way, since the work on the work 6 is started after the work start position of the robot 1 on the work 6 is corrected by the direct operation of the worker 4, the work 4 can correct the work position shift. Therefore, the work position shift can be eliminated, and the yield can be improved.
Further, by installing the enable device 13 like the direct operation device 8, the stage where the worker 4 approaches the robot 1, the stage where the worker 4 directly operates the robot 1, and the worker 4 leaves the robot 1. Safety can be ensured at the stage.

  FIG. 5 is a flowchart showing a processing procedure of a third robot guiding method for carrying out the present invention. FIG. 6 is a block diagram showing the configuration of the third robot system for carrying out the present invention. In FIG. 6, reference numeral 14 denotes a mat type unmanned confirmation sensor. The unmanned confirmation sensor 14 is a sensor that detects an intrusion by turning on a switch according to the weight of the person when a person or the like enters the mat area. Further, although the mat type unmanned confirmation sensor 14 is used in FIG. 6, an area sensor using a laser or the like can also be used as a sensor for confirming unattended. The other components are denoted by the same reference numerals as those in FIG.

The method of the present invention will be described step by step with reference to FIG.
First, in step S501, the robot 1 is regeneratively operated, and preparations are made until immediately before direct operation. Unmanned confirmation by the unmanned confirmation sensor 14 is performed as a starting condition for the regeneration operation. FIG. 6A shows the state of step S <b> 501, and the worker 4 is at a safe position away from the robot 1. Even if the operator 4 accidentally enters the safety fence 7 during the regeneration operation, the unmanned confirmation sensor 14 is activated, and the RC 2 stops the regeneration operation of the robot 1 urgently to ensure the safety of the worker 4. At the same time, an alarm is generated and the cause of the stop is specified.

  Next, in step S502, the robot 1 is temporarily stopped from being replayed, the function of the unmanned confirmation sensor 14 is disabled, and the robot control method of RC2 is switched so that a direct operation is possible. This switching is performed by executing a direct operation command registered in the work program. Moreover, since the function of the unmanned confirmation sensor 14 is invalidated by this switching, even if the operator 4 enters the safety fence 7 for direct operation, the RC 2 does not generate an alarm.

  Next, in step S503, the worker 4 enters the safety fence 7, and the worker 4 directly operates the robot 1 as one work of the regeneration operation to perform position correction. FIG. 6B shows the state of step S503.

  Next, in step S504, the operator 4 moves away from the robot 1 and presses the playback operation restart button 9 outside the safety fence 7, so that the RC 2 enables the function of the unmanned confirmation sensor 14, and the vicinity of the robot 1 is unmanned. After confirming that the servo power is turned on, the reproduction operation of the robot 1 is resumed. The instruction to resume the work program for the regeneration operation is resumed immediately after the instruction stopped in step S502. FIG. 6C shows the state of step S504, and in FIG. 6C, the playback operation restart button 9 is equipped on the RC 2 outside the safety fence 7. Since the function of the unmanned confirmation sensor 14 is validated, even if the operator 4 enters the safety fence 7 by mistake, the unmanned confirmation sensor 14 is activated, the RC 2 generates an alarm, and the robot 1 performs the regenerative operation. An emergency stop is performed to ensure the safety of the worker 4.

In this way, since the work on the work 6 is started after the work start position of the robot 1 on the work 6 is corrected by the direct operation of the worker 4, the work 4 can correct the work position shift. Therefore, the work position shift can be eliminated, and the yield can be improved.
In addition, since the unmanned confirmation sensor 14 performs unmanned confirmation during the regenerating operation in which the worker 4 should not enter the safety fence 7, if the worker 4 has entered if it should not enter the safety fence 7. The safety of the operator 4 can be ensured by urgently stopping the regeneration operation of the robot 1.

  Since the procedure for correcting the position of the robot through a person during the regenerative operation is taken, the recovery process in the event of any problem during the regenerative operation can be interspersed with humans. .

It is a flowchart of the 1st robot guidance method which implements this invention. It is a block diagram of the 1st robot system which implements this invention. It is a block diagram of the direct operation apparatus which implements this invention. It is a flowchart of the 2nd robot guidance method which implements this invention. It is a flowchart of the 3rd robot guidance method which implements this invention. It is a block diagram of the 3rd robot system which implements this invention. It is an example of a guidance trajectory of the present invention and a passing trajectory of a robot.

Explanation of symbols

1 Robot 2 RC
3 PP
4 Worker 5 Worktable 6 Work 7 Safety fence 8 Direct operation device 9 Playback operation resumption button 10 Robot tip 11 Holding unit 12 Force sensor 13 Enable device 14 Unattended confirmation sensor

Claims (4)

A robot system comprising: a robot; and a robot control device that includes a direct operation device that guides the robot to a wrist tip of the robot, and that controls the operation of the robot based on a work program in which the operation of the robot is registered in advance. In the robot guidance method,
The direct operation device includes an enable device that controls a permission state in which the robot operation is permitted and a prohibition state in which the robot operation is prohibited;
A first stage in which the robot stops in the middle of a replay operation based on a pre-registered work program;
A second step of placing the robot in the permitted state by operation of the enable device;
A third stage of guiding the robot by operating the direct operation device in the permitted state;
A fourth stage of placing the robot in the prohibited state by operation of the enable device;
A robot guidance method comprising the fifth stage in which the robot continuously starts a reproduction operation based on the work program.   The robot guidance method according to claim 1, wherein the stop in the middle of the reproduction operation in the first stage is a guidance command registered in advance in the work program.   The robot guidance method according to claim 1, wherein the stop in the middle of the reproduction operation in the first stage is an input to an input device provided in the robot control device. 2. The robot guidance method according to claim 1, wherein the continuation of the reproduction operation based on the work program of the robot in the fifth stage is based on the absence of an operator in the vicinity of the robot as an activation condition.

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