JP2004237370A - Robot control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a robot control device which verifies whether an operational track length of a robot working section falls within a predetermined range, and issues a warning if the length falls outside the range, thereby to urge the operator to re-correct the length. <P>SOLUTION: The robot control device 1 for controlling robot operation according to a working program instructed beforehand, comprises a working section length detecting means 10 for detecting the length of the working section in the working program, a working section length allowable range setting means 11 for setting an allowable range of the length of the working section, and a working section length comparing means 12 for comparing the operational track length of the working section detected by the working section length detecting means 10 with the allowable range. At the time of correction of the working program, if the operational track length of the working section after correction falls outside the allowable range, the control device issues a warning. Then the operational track length of the working section detected by the working section length detecting means 10 is displayed on a screen of a display device provided for an instructing means 23. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a teaching control type robot control device.
[0002]
[Prior art]
Today, industrial robots of the teaching reproduction system are frequently used in many manufacturing sites, and contribute to improvement in productivity through labor saving or improvement in production speed. In a manufacturing process in which an industrial robot is used, there is a field in which the amount of work or the amount of production is grasped by length. Examples include welding, cutting, and sealing.
For example, in the field of arc welding, the joint length (welding length) of a welding object is selected at the design stage of the object, and a necessary and sufficient length is selected. Care must be taken to form a fixed length weld joint. If the welding length is insufficient, the strength of the joint will be insufficient, and if the welding length is excessive, the working time will be long and the productivity will be reduced.
As an example of an apparatus for managing the work length by such a robot, there is Patent Document 1 previously filed by the applicant of the present application. Patent Literature 1 discloses that a work program of an arc welding robot is analyzed and a motion locus of the robot (in this case, a locus of a tip of a welding torch) is divided into a work section (in this case, a section in which welding is actually performed) and an air cut. A robot control device is disclosed which divides into sections (mere movements and does not perform welding), obtains the length of an operation trajectory of a work section, and presents it to an operator.
[0003]
[Patent Document 1]
JP 2001-222309 A
[Problems to be solved by the invention]
However, the conventional robot controller has a function of calculating and displaying the length of the work section, that is, the welding length, but determines whether or not the welding length is within an allowable range specified by design. Therefore, the quality of the welding length was left to the operator. In other words, the operator has checked the welding length displayed on the robot control device with respect to the work drawing of the welding target or the like to determine whether or not the welding length is good. Therefore, there is a problem that a human error occurs.
In the field of the automobile industry and the like, a specific product is produced for several years (that is, a period determined by the interval between model changes of a vehicle), and the welding robot repeatedly executes the same work program during that period. . However, in order to ameliorate minor inconveniences that occur during the production work, the work program is modified by workers at the site. At this time, there is a feeling of correction on the safe side as a natural psychology of human beings. For this reason, it is considered that it is better to make the welding length longer than the shortage of the welding length due to an error at the time of the correction, and the correction tends to be made so that the welding length becomes longer. There is a problem that even if the welding length is slightly increased by one correction, if the correction is repeated, the working time is increased, that is, the productivity is reduced.
Therefore, the present invention provides a robot control device capable of verifying whether or not the length of a work section of a robot is within a prescribed range, issuing an alarm when the length is outside the range, and prompting the operator to correct again. The purpose is to:
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, an invention according to claim 1 is a robot control device that controls the operation of a robot according to a work program taught in advance, wherein the work section length detects the length of the work section in the work program. Detecting means, working section length allowable range setting means for setting an allowable range of the working section length, and working section length for comparing the working section length detected by the working section length detecting means with the allowable range A comparing means is provided, and when the work program is corrected, a warning is issued when the length of the work section after the correction is out of the allowable range. According to a second aspect of the present invention, the length of the work section detected by the work section length detecting means is displayed on a screen of a display provided in the teaching means.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a robot control device showing a first embodiment of the present invention. The robot control device 1 is a device that controls the robot 2 and the welding power source 3 to control an arc welding operation by the robot 1. The robot controller 1 includes a central processing unit (hereinafter referred to as a CPU) 20. The CPU 20 includes a ROM 21, a RAM 22, a teaching unit 23, an arithmetic processing unit 24, an I / O interface 25, and an axis controller 26 via a bus 27. Connected. Various control programs to be executed by the CPU 20 are stored in the ROM 21. The RAM 22 is a non-volatile memory, and stores teaching data input from the teaching means 23 and data such as set values of various parameters. The teaching means 23 has a numerical control / display, a lamp, and operation buttons necessary for operating the robot 2. The arithmetic processing unit 24 calculates an operation locus of the robot 2 and various control conditions. The I / O interface 25 communicates control signals and status signals with the welding power source 3, and outputs an alarm signal to the alarm output means 29. The axis controller 26 is connected to a servomotor (not shown) of each axis via a servo circuit 28 of each axis of the robot 2 to operate the robot 2. The above components are basically the same as the control device of the conventional arc welding robot. In addition to the above, the robot control device of the present invention includes a work section length detection means 10 and a work section length comparison means 12 inside the arithmetic processing unit 24 and a work section length allowable range setting means 11 inside the teaching means 23. It is characterized by that.
[0007]
FIG. 2 is a diagram illustrating the operation of the robot control device. The work section length allowable range setting means 11 provided in the teaching means 23 is a means by which an operator inputs the allowable range of the work section length, that is, the upper and lower limits of the welding length. The means may be a means by which a worker makes a key input, or a means for transferring data online or offline from a higher-level system (so-called CAD or CAM system). The work section length detecting means 10 is inside the arithmetic processing unit 24, analyzes the work program, and calculates the length of the work section by calculation. The work section length comparison means 12 is also included in the arithmetic processing unit 24, and compares the length of the work section obtained by the work section length detection means 10 with the allowable range set by the work section length allowable range setting means 11, and performs detection. If the length of the work section does not fall within the set allowable range, an alarm is issued through the alarm output means 29.
[0008]
FIG. 3 is a flowchart illustrating a method of managing the length of a work section according to the present invention. Hereinafter, the management method will be described with reference to this flowchart.
(STEP 1) First, a work program is created as in the prior art.
(STEP 2) After the work program is created, the work program is analyzed by the work section length detecting means 10, and the length of the work section is automatically calculated, which becomes the reference value of the work section length allowable range. Here, as an example, the length of the work section is 300 mm.
(STEP 3) Next, a work section length allowable range is set using the calculated work section length as a reference value. For example, the work section length allowable range is set to ± 5 mm. In this case, the upper limit is 305 mm and the lower limit is 295 mm.
(STEP 4) The work section length monitoring operation is started by setting the work section length allowable range.
(STEP 5) When the worker corrects the work program and corrects the robot position (for example, the welding start point) in the work section, the work section length detecting means 10 operates to detect the corrected work section length. Then, it is monitored whether it is within the allowable range of the work section length set in STEP3.
(STEP 6) If not within the working section length allowable range, an alarm is issued via the alarm output means 29. The operator can correct the work program without worrying about whether the length of the work section is within the specified value.
[0009]
By executing the above steps, when modifying the work program, it is monitored whether the length of the work section is within the specified range, and if it is out of the range, an alarm is issued, so that the length of the weld joint can be corrected. Can be reliably set to the prescribed value, so that welding quality can be improved.
[0010]
FIG. 4 is a configuration diagram of a robot control device according to a second embodiment of the present invention. It is characterized in that the work section length display means 13 is added to the teaching means 23 in addition to the configuration of the robot control device shown in FIG. The work section length display means 13 can display the length of the work section in characters or graphics using a part of the screen of an LCD display disposed on the surface of a programming pendant (teaching means). Good.
FIG. 5 shows an example of a display screen of the teaching means 23. FIG. 5A shows a state before the length of the work section is changed, and FIG. 5B shows a state after the length of the work section is changed. In steps 3 and 5 of FIG. 5A, the length of the work section currently registered in the work program is displayed (L = 300 mm).
A work section length display means 13 is provided at the upper part of the display screen, and displays the length of the motion trajectory (L = 302 mm) of the current work section where the robot 2 is operated. The operator can correct the position of the robot while looking at the motion trajectory length of the work section displayed on the work section length display means 13. Next, when the robot position is corrected in this state (the length of the work section is changed), the robot position is corrected without warning because it is within the set work section length allowable range (300 mm ± 5 mm). The state shown in FIG. That is, in FIG. 5B, in steps 3 and 5, the work section length whose registration in the work program has been updated is displayed (L = 302 mm).
As described above, since the work section length display means 13 for displaying the current work section length on the screen of the teaching means 23 is provided, when correcting the robot position of the work section, The movement locus length can be instantaneously confirmed, the robot position can be corrected in a short time, the teaching work of the robot can be facilitated, and the motion locus length in the working section can be reliably set to the specified value.
[0011]
In the above description of the embodiment, an example in which the welding length is managed in the welding robot has been described. However, the application field of the present invention is not limited to the welding robot. It is needless to say that the present invention can be applied to robots used for fields in which the length of a work section needs to be controlled, for example, cutting, sealing, and the like.
[0012]
As described above, according to the robot controller of the present invention, when modifying a work program, it is monitored whether or not the length of a work section is within a specified range. By issuing an alarm, the length of the work section can be reliably set to the prescribed value. Therefore, the length of the welding joint can always be controlled to a specified value, so that welding quality can be improved.
According to the robot control device of the second aspect, when correcting the work program, the length of the work section can be instantaneously confirmed and the position of the robot can be corrected in a short time. In addition to being easy, the length of the work section can be reliably set to the specified value.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a robot control device according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a first embodiment of the present invention.
FIG. 3 is a flowchart illustrating a work section length management method according to the present invention;
FIG. 4 is a configuration diagram of a robot control device according to a second embodiment of the present invention.
FIG. 5 is an example of a screen of a teaching means showing a second embodiment of the present invention.
[Explanation of symbols]
1 robot control device, 2 robots, 3 welding power supply, 10 work section length detecting means,
11 work section length allowable range setting means, 12 work section length comparison means,
13 work section length display means, 20 CPU, 21 ROM, 22 RAM, 23 teaching means,
24 arithmetic processing units, 25 I / O interface, 26 axis controller, 27 bus,
28 servo circuits, 29 alarm output means

Claims (2)

In a robot control device that controls the operation of the robot according to a work program taught in advance,
A work section length detecting means for detecting a work section length in the work program; a work section length allowable range setting means for setting an allowable range of the work section length; Work section length comparing means for comparing the length of the work section with the allowable range,
A robot control device, wherein when the work program is corrected, a warning is issued when the length of the work section after the correction is out of the allowable range. 2. The robot controller according to claim 1, wherein the length of the work section detected by the work section length detecting means is displayed on a screen of a display provided in the teaching means.

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