JPH04268607A - Off line teaching method for robot - Google Patents

Abstract

PURPOSE:To always smoothly change the angle of a joint to continuously move it along a curve by equalizing the direction and the position of a working tool attached to a robot and automatically converting attitude data to operation data of a different angle of the joint in the case of the quick operation change. CONSTITUTION:A personal computer 2 reads an attitude data part in the first row of a file, which a CAD system 1 outputs, into a variable Dpre and reads that of the next row into a variable Dcur. The personal computer 2 evaluates a difference >>Dpre-Dcur>> between these variables Dpre and Dcur. IF this difference is larger than reference value, the personal computer 2 recognizes the quick change of the angle of the joint and converts attitude data to alternate attitude data to substitute it into the variable Dcur and updates contents of the variable Dpre to data contents of the variable Dcur. Otherwise, the personal computer 2 does not convert attitude data to alternate attitude data.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for off-line teaching a robot.

0002

[Background Art] Conventionally, in order to teach a work robot the content of its work, a worker carries a teaching pendant, enters the robot's operating range, and teaches while manually operating the desired robot itself. The method was common. However, this method has a major economical problem as it requires the movable robot to pause for long periods of time for teaching, and furthermore, it is physically and mentally stressful for the instructor to work for long hours in a dangerous place. It was also a big burden on me.

[0003] Therefore, a method has been developed in which a model of the robot or workpiece is built on a computer that is independent of the robot controller, and the model is used to teach the robot. The method of converting to a data format is described in Japanese Patent Application Laid-Open No. 63-2739.
This is already known from Publication No. 07 and the like.

0004

[Problem to be solved by the invention] However, JP-A-63-
In the conventional method as seen in Publication No. 273907, an actual robot cannot perform the motion trajectory outputted from the CAD system, especially during the motion trajectory in which the power tool moves along a continuous curved path. , or may include sudden changes in joint angles that would cause problems in machining when executed, and inconvenient parts had to be taught using a direct teaching method (teaching by manual operation).

[0005] Robot motion commands can be broadly classified into movement commands that include position and orientation data for movement, motion commands other than movement, and control commands such as speed and other parameter settings. However, the order of these motion command sequences may differ between the output order from the CAD system and the order specified in the language used by the robot, so the operator may have to rearrange the order using an editing device, etc. There was a need.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide offline teaching for robots in which the joint angles always change smoothly and it is possible to make continuous curved movements. It is possible to provide an offline teaching method for robots.

[0007]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides that when a robot is operated using robot motion data outputted from a CAD system, if there is a sudden change larger than a reference amount, , is characterized by having a process of automatically correcting and converting the direction and position of the working tool attached to the robot into motion data of different joint angles.

[0008]

[Operation] According to the present invention, when the robot is operated using the robot motion data output from the CAD system,
If there is a sudden change larger than the standard amount, there is a process to correct and convert the motion data of a different joint angle by keeping the direction and position of the work tool attached to the robot the same.
When operating the robot using motion data from a CAD system, if a large and sudden change occurs and the change is larger than the standard amount, it can be automatically corrected and converted to alternative motion data, making it possible to correct inconvenient points. There is no need to teach using a direct teaching method.

[0009]

[Examples] The present invention will be explained below with reference to Examples. Figure 1 shows the configuration of a teaching system using the method of the present invention.
The illustrated teaching system includes a CAD system 1, a personal computer (hereinafter abbreviated as personal computer) 2, a robot controller 3, a robot 4, a detector 5, and an interface device 6 for the detector.

The CAD system 1 is composed of a CPU 10, a graphic display 11, a storage device 12, a keyboard 13, and a mouse 14, and has a three-dimensional shape definition function and a robot motion simulation function as a system. There is. On the other hand, PC 2 has CPU2
0, a display 21, a storage device 24, a keyboard 22, and a mouse 23.

Next, the operation of the overall functional blocks of the above system will be explained based on the flowchart shown in FIG. First, in the CAD system 1, the shapes of a robot model and a workpiece model are defined in step S1, and then the robot motion is taught using the robot model and workpiece model in step S2. When the teaching is completed, the taught motion is displayed in a simulation on the graphic display 11 in step S3, and it is checked whether there is any inconvenient motion.

[0012] Subsequently, the teaching data file output from the CAD system 1 is transferred to the personal computer 2, and the process proceeds to step S.
After converting the data into a data format that can be interpreted and executed by the target robot 4 by the conversion means constituted by the personal computer 2 in step S5, the robot controller 3
and the robot 4 is operated in step S6. Next, the detailed operation of the rapid joint angle change correcting means included in the converting means will be explained based on FIG. 3.

First, in FIG. 3, in step S1 the CAD
The posture data part in the first line in the file output from system 1 is read into the variable Dpre, then in step S2 the posture data part of the next line is read into the variable Dcur, and in step S3 both Dpre and Dcur are read. The magnitude of the difference |Dpre−Dcur| is evaluated. If the difference is larger than the reference amount, it is assumed that the joint angle has changed rapidly, and in step S4 the data is converted to alternative posture data and substituted into the variable Dcur.In step S5, the content of the variable Dpre is changed to the data content of the variable Dcur. Update to. Further, if the difference is smaller than the reference amount, conversion to alternative posture data is not performed.

In this way, finally, conversion to the data format for the target robot is performed in step S6. The procedure from step S2 of reading the posture data of the next line to step S7 of converting to the data format for the target robot is repeated until the end of the file.

In the embodiment, the function of the correction means for sudden joint angle changes is obtained on the personal computer 2, but CA
Of course, it can be implemented using the D system 1 or other computers. FIG. 4 shows a motion simulation on the CAD system 1 when the work tool of the robot 4 moves from point a to point b along a continuous curved path, and c1
When moving from point c2, the joint angle representing the posture of the work tool of robot 4 changes rapidly, and the CAD shown in FIG.
This can also be seen from the motion locus data of the X, Y, and Z coordinate values in the reference coordinate system and the Euler angles of ψ, θ, and Φ output from the system 1. The part A surrounded by a frame in FIG. 5 shows a sudden change in the joint angle.

In this case, in the procedure shown in FIG. 3, the orientation and position of the working tool attached to the wrist of the robot 4 are corrected to other equivalent joint angle data. 6 and 7 show an example where the joint angle representing the posture of the work tool of the 5-axis articulated robot 4 suddenly changes, and the posture axis of the robot 4 is Alternative posture data of the working tool of the robot 4 represented by the axis C and the axis D and shown by the solid line changes the angle of the posture axis C by 180 degrees (the working tool of the robot 4 shown by the dotted line in the figure). , is determined by mechanistically correcting the angle of the attitude axis D. The flowchart in FIG. 8 shows a process of converting the angles of the posture axes C and D into alternative posture data when the joint angles representing the posture of the working tool of the robot 4 shown in FIGS. 6 and 7 suddenly change.

Next, the operation of the operation command order changing means included in the converting means will be explained with reference to the buffer contents shown in FIG. 9 and the flowchart shown in FIG. First, the buffer 2
1 is provided.

In FIG. 7, one line is read from the CAD output file in step S1, and instructions are determined in step S2.
After branching, in step S3 in the flowchart surrounded by a broken line A, the data is converted into the target robot data format, and is stored in the buffer 21 in step S4. In step S5, the line number in the CAD file is stored, and in step S6, the line number in the CAD file is advanced by one line.
Read one line.

In step S6, it is determined whether the read data is a sequence of points within the same curve, and if it is the sequence of points on the same curve, it is determined in step S7 whether or not it is a speed command. If it is a speed command, it is converted into the target robot data format in step S8, and written to the buffer 21, and the process returns to step S5. If the speed command is not a speed command, the speed command is changed to the data format of the target robot in step S9, and is written to the buffer 21 in step S10.

[0020] In this way, the series of processes is repeated until the command to move the point sequence within the same curve is completed. The instruction strings stored in the buffer 21 at this point are arranged in the order of the instruction strings output from the CAD system. In step 11, the line number in the CAD file is returned by one line.
After that, based on the flowchart surrounded by the broken line B, in steps 12 and 13, the speed command line and the curve movement command line are read out from the buffer 21 in the desired order and written to a file, and the This results in a sequence of instructions arranged in the order appropriate to the language used.

[0021] In this case, the effort required to manually rearrange the order of the instruction sequence using an editing device or an editing function on the robot controller can be reduced.

[0022]

[Effects of the Invention] The present invention provides the following advantages: When a robot is operated using robot motion data output from a CAD system,
If there is a sudden change larger than the standard amount, there is a process to correct and convert the motion data of a different joint angle by keeping the direction and position of the work tool attached to the robot the same.
When operating the robot using motion data from a CAD system, if a large and sudden change occurs and the change is larger than the standard amount, it can be automatically corrected and converted to alternative motion data, making it possible to correct inconvenient points. This has the advantage that there is no need to teach using the direct teaching method.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a teaching system using the method of the present invention.

FIG. 2 is a flowchart of the overall operation of the teaching system shown in FIG. 1;

FIG. 3 is a flowchart of the operation of the means for correcting sudden joint angle changes according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a simulation of sudden changes in joint angles used in one embodiment of the present invention.

FIG. 5 is another explanatory diagram of a sudden change in joint angle according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram of a simulation showing conversion of a five-axis articulated robot to alternative posture data.

FIG. 7 is an explanatory diagram of a simulation showing conversion of a five-axis articulated robot to alternative posture data.

FIG. 8 is an explanatory diagram of the process of converting the five-axis articulated robot into alternative posture data.

FIG. 9 is a configuration diagram of a buffer of means for sequentially exchanging operation instruction sequences used in an embodiment of the present invention.

FIG. 10 is a flowchart of the operation of a means for sequentially exchanging operation command sequences used in an embodiment of the present invention.

[Explanation of symbols]

1 CAD system 2 Personal computer 3
Robot controller 4 Robot 5 Detector 6 Interface

Claims (1)

[Claims] Claim 1: When operating the robot using the robot's motion data output from the CAD system, if there is a sudden change larger than the reference amount, the direction and position of the work tool attached to the robot should be changed to the same direction. A robot offline teaching method characterized by having a process of automatically correcting and converting motion data of different joint angles.