JPH06134684A - Teaching method of robot track - Google Patents

Abstract

PURPOSE:To provide a method to efficiently teach a robot track for generating track information with less error by way of lightening burden of a user at the time of inputting and editing information concerning the robot track. CONSTITUTION:By displaying a visual image of three-dimensional positional relation of a holding point and a working point of a tool in a display device of a computer system (S100-S101), and by displaying a visual image by way of changing the threedimensional positional relation in accordance with optional changing operation against the three-dimensional positional relation designated on a screen of the display device, a robot track is created from a contact point locus in accordance with the three-dimensional positional relation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and system for teaching a robot trajectory, and more particularly to a robot teaching technical field, a robot manipulator control technical field,
Also, it belongs to the field of human interface technology related to human-machine interaction, and specifically, a robot work teaching device (information input interface device) that efficiently conveys to the robot the work that the robot user wants the robot to perform. A method for teaching a used robot trajectory.

More specifically, the present invention relates to an improved method for efficiently generating trajectory information of a general machining operation having a trajectory that conforms to the shape of a target workpiece based on the display of a computer.

[0003]

2. Description of the Related Art Conventionally, there are a direct teach method, a remote teach method, an indirect teach method, and an offline teach method for teaching position / orientation information as a robot trajectory teaching (cited document: "Robot Engineering Handbook", The Robotics Society of Japan). Ed., Issued by Corona in 1990, pp519-529).

The above-mentioned first conventional direct teach method is a method of directly moving the arm portion of the robot. The above-mentioned second conventional method, the remote teach method, is a method of teaching at a location away from the robot body without directly touching the robot arm with a teaching device called a teaching pendant. In the above-mentioned third conventional method, the indirect teach method, a manipulation arm dedicated to teaching is prepared, and the hand portion of this arm is operated so as to move along a required path. This is a method of teaching by storing. The above-mentioned fourth conventional method, the offline teach method, is a method of teaching away from the actual work environment without using a robot that actually performs the work. in this way,
Since the trajectory of the robot can be generated by using the geometrical shape information of the work whose shape has been already designed, it has an advantage that the burden on the operator can be greatly reduced.

[0005]

However, in any of the above-mentioned first to third conventional methods, the entered trajectory information is first displayed, and in order to carry out the changing work, the trajectory information represented by numerical values is used. It is displayed on the character display device, and the user needs to specify the displayed line and change the numerical value. Therefore, the user has to discover the teaching point at a desired position from the information of the teaching point expressed by a numerical value, which has a disadvantage of compelling the user. In order to correct the teaching point to the desired position / orientation, it is necessary to change the numerical value directly or to retrieve new data of the point again by using the above teaching method, which complicates the operation. Beckoning
This may reduce the efficiency of teaching work.

Further, since the above-mentioned fourth conventional method, the offline teach method, presupposes the geometrical shape information of the work already generated by CAD or the like in the trajectory teaching, the shape information of the work by CAD is used. It is difficult to apply to difficult work.

When the trajectory generated by the off-line teach method is operated in a real work environment, the manipulator,
Errors often occur due to error factors in the actual environment such as jigs and workpieces. In order to reduce the error, measures such as meticulous calibration of the manipulator are taken, but the absolute accuracy driven by the calibration is generally large compared with the repeat accuracy of the manipulator, and actual matching is necessary. The correction of the orbit by matching the actual products requires a complicated operation as in the above direct teach method.

Furthermore, the shorter the update cycle of the manufacturing line to accommodate a new product, the larger the ratio of the drive cost of the robot trajectory teaching becomes, and the efficiency of the trajectory teaching becomes a problem. In addition, editing the trajectory entered first due to the error of the actual environment described above to the final trajectory
The adjustment work occupies a large proportion of the entire trajectory teaching, and the improvement of the human interface in this portion has a great influence.

In addition, the above-mentioned conventional methods teach the position / orientation information of the manipulator in any case, and in addition to the position / orientation of the work of the robot, the target of force and the relative softness between the manipulator and the work. It is not possible to directly give the information associated with the exercise such as the compliance matrix for setting the height.

In any of the methods, there is no choice but to insert a parameter setting command before or after the command for giving the position / orientation of the teaching point, or to give it as an argument of the command giving the teaching point. Editing the information associated with such exercise is generally performed by selecting the command line using a text editing editor and rewriting the line, which requires labor to search and select the command line. Further, since similar commands appear in many places, there is a problem that it takes time to find a command to be really corrected, or there are many errors.

The present invention has been made in view of the above points,
It is an object of the present invention to provide a method for teaching a robot trajectory that solves the above problems, reduces the burden on the user when inputting / editing information related to the robot trajectory, and efficiently generates trajectory information with few errors. To aim.

[0012]

FIG. 1 shows a diagram for explaining the first principle of the present invention.

The present invention is a method for creating a robot trajectory using a computer system having a display device, wherein a visual representation of a three-dimensional positional relationship between a gripping point of a tool and an action point is provided in the display device of the computer system. The dynamic image (step 101), and changes the three-dimensional positional relationship based on an arbitrary change operation for the three-dimensional positional relationship designated by the user on the screen of the display device (step 102).
A visual image is displayed (step 103), and a robot trajectory is generated from the contact point trajectory based on the three-dimensional positional relationship (step 104).

Further, according to the present invention, a position on the robot trajectory in which the tool held by the robot is replaced in the robot trajectory information including the tool information is detected and the detected tool name change position is the trajectory up to the position of the tool changer. , And the tool changer replaces the tool and adds a trajectory to the returning position, and a visual image of the added trajectory is displayed.

FIG. 2 shows a diagram for explaining the second principle of the present invention.

The present invention is a method for creating a trajectory of a robot by using a computer system having a shape input device for inputting the shape of a work and a display device. The local shape information including the locus of the contact point is input (step 200), and the accurate position of the contact point where the tool should contact the work is recognized as the contact point position information based on the input local shape information (step 200). 201), based on the contact point position information, the traveling direction of the robot trajectory, and the local shape information of the work, a local coordinate system at the position of the contact point with the tool on the work is generated (step 202), and in the display device of the computer system. The local shape information of the workpiece, the contact point trajectory information of the tool, and the local coordinates at the contact point position input at the same time are converted into a visual image at the same time. -Up 203) display (step 20
4) Edit based on the change operation for the robot trajectory information designated on the display screen (step 205), and display a visual image of the robot trajectory information on the display device (step 206).

[0017]

The present invention is a parameter for defining the shape of a robot tool (the spatial positional relationship between the contact point and the grip point on the tool).
By capturing the parameters from the user, visually displaying and modifying the captured parameters using a graphical user interface, calculating the spatial positional relationship and contact point trajectory, and automatically generating the robot trajectory. ,
It becomes easy to understand the spatial positional relationship between the contact point and the grip point on the tool.

Further, according to the present invention, by automatically adding the trajectory until the tool is exchanged and returned to the position where the tool is exchanged by including the information of the tool type in the trajectory information. Can concentrate on the recognition of trajectories for machining workpieces.

Further, according to the present invention, the contact point locus is recognized based on the shape information of the work, and the local coordinate system is uniquely set at the contact point based on the shape of the contact point and its surroundings and the traveling direction of the contact point locus. By generating the local coordinate system, the wrist trajectory of the robot can be generated if the spatial positional relationship between the contact point between the tool and the work of the robot and the gripping point is given.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A trajectory teaching method of the present invention will be described below with reference to the drawings.

FIG. 3 shows a computer according to an embodiment of the present invention.
The configuration of the system and robot system is shown. In the figure, the robot system comprises a robot manipulator 1, a sensor fixing jig 2, a laser range scanner 3, and an irradiation laser beam 4, and a computer system 5
Is a display device 6, a keyboard 7, a keyboard connection cable 8, a mouse 9, a mouse connection cable 10, a processing device 1
1, a manipulator / controller 12, and a computer connection cable 13.

Processor 11 of computer system 5
Preferably includes a graphic processor, a storage device, and a central processing unit (not shown), and a workstation is used in this embodiment. A display device 6, a keyboard 7, and a mouse 9 which is a graphic pointing device are connected to the processing device 11. Display device 6
May use a color monitor or a black and white monitor.
The keyboard 7 is preferably a standard computer keyboard and is connected to the processing unit 11 by a keyboard connection cable 8.

Although the mouse 9 is used as the graphic pointing device in the present embodiment, the present invention is not limited to this example, and any graphic pointing device such as a light pen, a touch screen, a trackball, a dial button or the like can be used. May be.

A laser range scanner 3 is connected to the tip of the robot manipulator 1. robot·
The manipulator 1 has an encoder (not shown) for each joint axis.
It is desirable to include. Robot by encoder
The position / orientation of the manipulator 1 can be obtained by kinematic calculation. Robot manipulator 1
By being controlled in the damper mode, the operator can grasp the laser range scanner 3 and move the laser range scanner 3 to any position and orientation within the operable range of the robot manipulator 1. The shape of the work 14 on the work table 15 is measured by moving the laser range scanner 3 along the trajectory of the working operation and irradiating the laser light during the movement.

Information indicating the shape of the work 14 obtained by one laser irradiation is called frame information. The position / orientation of the laser range scanner 3 when the laser light is emitted is determined by the value of the encoder included in the robot manipulator 1 at that time. The measured sensor information and the position / orientation information of the laser range scanner 3 are transferred to the computer system 5.

The computer system 5 calculates the position information of the surface of the shape of the work in the world coordinate system by calculating the frame information measured by laser light irradiation and the position / orientation information of the laser range scanner 3. . The positional information on the surface of the work 14 is called a surface model.

In the present invention, the robot manipulator 1 and the laser range scanner 3 are used to obtain the surface model of the work shape. To realize the present invention, a CAD (Computer Aided Design) system or 3 is used.
Any surface model generator, such as a two-dimensional laser digitizing system, may be utilized to implement the method of the present invention.

The robot manipulator 1 is connected to a manipulator controller 12, and the manipulator controller 12 is a computer system 5.
The robot manipulator 1 is controlled so as to attain the target position / orientation based on the position / orientation target value of the robot transferred from.

Further, in the present embodiment, the robot manipulator 1 is a 6-DOF vertical articulated robot, but any robot manipulator capable of controlling the wrist to a target position / posture can be used. Good.

FIG. 4 is a diagram for explaining the operation of one embodiment of the present invention. A computer display screen 16 is shown in FIG.
Is displayed. The computer display screen 16 includes a main display window 17, a menu bar 18, a pull-down menu 19, a mouse cursor 20, a coordinate icon 21, a tool editing subwindow 23, a frame editing subwindow 24, a shape editing subwindow 25, and a selection button 26. , Selection button group 27, frame information 28,
A contact point trajectory 29 and a robot trajectory 30 are shown.

In the main display window 17 of the display screen 16, a large number of frame information obtained from the target work 14, a contact point locus 29 connecting the contact points defined in each frame information, and a robot trajectory. 30 is displayed. The frame information is composed of observation point groups included in the surface model, and the observation point groups included in this frame information are connected in order. In this embodiment, points constituting the edge of the work 14 in the frame information are contact points, and the contact point locus 29 is displayed by sequentially connecting the contact points.

The surface model of the work 14 is displayed by using any display method such as a plane patch method such as a triangular patch in addition to the display by a plurality of frame information as in this embodiment. May be.

Then, by clicking the menu bar 18 with the mouse cursor 20, the pull-down menu 19 is displayed.
Is displayed. The user specifies a command by selecting the command included in the pull-down menu 19 with the mouse cursor 20.

As a method of selecting a command, the present invention may be carried out by using a designation method based on another graphical user interface of the pull-down menu 19 as in this embodiment.

From the above, the command selection method is a so-called graphical interface standard, for example,
The present invention may be implemented using a tool box proposed by Apple Inc. or an OSF / Motif proposed by Open Software Inc.

The selection button group 27 includes a plurality of selection buttons 2.
It is composed of 6. The selection button 26 is used, for example, to specify whether to display frame information or not. In addition to the selection button, any user interface such as a menu dialog box may be used to specify the display on / off.

Next, the operation will be described.

The user is a robot controlled by a damper.
The robot manipulator 1 is moved so as to have a manipulator selection unit so that the locus which should be the locus of the contact point on the work 14 is always included in the scanning area of the laser range scanner 3. Regarding the movement of the robot / manipulator 1, the robot / manipulator 1 may be moved on a rough trajectory set by the user.

The laser range scanner 3 moves the work 14 at a constant interval or at a timing designated by the user while moving.
Measure the shape of. The information measured by the laser range scanner 3 at one time is called frame information (not shown). The position / orientation information in the world coordinate system of the laser range scanner 3 at the time when the frame information is measured is generated based on an encoder (not shown) installed in each joint of the robot manipulator 1. This position / orientation information is called robot position / orientation information. The measured frame information and the robot position / orientation information are sequentially transferred to the computer system 5, or the information during movement is stored and collectively transferred to the computer system 5 after the end of exercise.

The computer system 5 converts the frame information into the world coordinate system based on the transferred frame information and the robot position / orientation information, and displays it in the main display window 17 as frame information 28. Main display window 17
The frame group displayed in can be used by the user as shape information representing the shape of the work 14. The frame information 28 includes contact points. The user defines one contact point for each frame information through the user interface, and further displays a chain of contact point information as a contact point trajectory in the main display window 17. For this contact point trajectory, the user inputs the trajectory of the trajectory based on the contact point trajectory using the user interface.

The shape point locus and the trajectory are composed of a shape point and a teaching point, respectively. In the display screen 16, the frame information 28, the shape points, the shape locus 29, the teaching point, the trajectory 30, and the like are selection targets. In this case, the selection is performed by operating the mouse 9 to bring the mouse cursor moving on the screen over the selection target and then clicking the button of the mouse 9. The position / orientation of the selected target is operated by operating the mouse. Position and posture operations
You may perform using the input device of multidimensional data other than a mouse.

FIG. 5 shows the tool definition window side of one embodiment of the present invention. In the figure, in a dialog window frame 38 in the computer display screen 16, an attribute designation / display frame 31, an up / down button 32, an acceleration side up / down button 33, a control bar 34, a slider 3 are shown.
5, the tool definition window 53 displays the tool gripping coordinates 51 and the tool work coordinates 52.

In the figure, when the user defines a tool by using the trajectory editing system, the tool definition window 53 is clicked to swap the tool definition window 53 with the main display window 17, thereby creating the tool definition window 53. Is displayed. However, if the tool definition has already been performed, the menu (selection button group 2
Select the tool display from 7), activate the "tool library" command, select the target tool from the tool library, and display it in the tool definition window 53.

When a user newly defines a tool,
When the "define new tool" command is activated from the menu, the system displays the tool gripping coordinates 51 on the screen and at the same time displays the dialog window frame 38 for inputting the contact point position / orientation of the tool on the screen. The user is
The contact point position with respect to the tool gripping coordinate is specified using the X, Y, and Z input boxes of the dialog window frame 38. As a result, the contact point position is displayed on the screen, and the contact point and the grip point are connected by a straight line and displayed.

Since a contact point also exists on the work 14 which is the machining target of the tool, contact point coordinates are defined around the contact point of the work 14. The coordinates of the contact point of the work 14 are given by recognition from the shape described later. It is also possible for the user to give the contact point coordinates as shape information using the trajectory teaching system without recognition.

The user of the tool definition defines the attitude of the tool contact point coordinates at the contact point in order to define the contact attitude of the robot tool with respect to the work 14 in the dialog window frame 3
Designate using O, A, and T of 8. O, A and T represent Euler angles. Tool work coordinates 52 are displayed according to the contact attitude definition of the user. Each time the user changes the contact attitude, the displayed tool work coordinate 52 also changes.

The contact point on the shape point locus has contact point coordinates as its attribute. In order to provide the contact point coordinates, in this embodiment, the contact point coordinates are calculated based on the frame information.

FIG. 6 shows a flow chart of the contact coordinate processing of one embodiment of the present invention.

Step 10: The user uses the mouse 9 to select the locus of the contact point which gives the coordinates.

Step 11: With the contact point locus selected, the mouse 9 is operated, for example, to select a menu such as "Edit" in the menu bar 18 by pressing the mouse button, and the menu is kept pressed. Then, for example, if you click the command "posture calculation", "left (L)",
Since three submenus of "right (R)" and "center (C)" are displayed, one of them is selected according to the target work.

Selection of any one of "left", "right" and "center" from such three submenus is called LRC selection in this embodiment. The LRC selection is for selecting any of the three rules that determine the coordinates on the contact point. The three types of rules are described below.

"L rule": The direction of travel of the contact point is defined as the X direction, and the direction perpendicular to the X direction included in the left surface of the travel direction is defined as the Z direction to determine the coordinates.

"R rule": The coordinate of the contact point is determined with the X direction as the traveling direction and the Z direction as a direction included in the right surface of the traveling direction and perpendicular to the X direction.

"C rule": The traveling direction of the contact point is defined as the X direction, and the direction toward the outside of the work 14 at the center line of the intersection line with the left and right surfaces in the traveling direction on the plane perpendicular to the X direction is the Z direction To determine the coordinates.

Step 12: The frame information including the contact points obtained from the work 14 is taken out.

Step 13: The contact point is determined from the extracted frame information.

Step 14: By executing the command, the traveling direction of the contact points is determined as the X direction for all the contact points included in the contact point trajectory. Thereby, the traveling direction vector of the contact point is determined.

Step 15: According to the selected LRC rule, the frame direction vector is determined from the frame information including the contact point.

Step 16: If the selected rule is the L rule or the R rule, the process proceeds to step 18.

Step 17: When the selected rule is the C rule, the direction toward the outside of the work 14 is the Z direction with respect to the center line of the intersection line with the left and right surfaces in the traveling direction on the surface perpendicular to the X direction. To decide. Go to step 19.

Step 18: When the selected rule is the L rule or the R rule, the vector direction perpendicular to the X direction on the plane formed by the direction and the frame direction vector is determined as the Z direction.

Step 19: If the X and Z directions are determined, the attitude of the coordinate system is also determined, so the Y direction is also determined.
When this coordinate system determination operation is performed for all contact points, command execution ends. At this time, if the attitude of each contact point is displayed, the new display attitude is displayed.

In this embodiment, the user selects the trajectory generation command to position the tool so that the contact point coordinates of the work 14 input by the tool definition match the contact point coordinates at the contact point of the work 14. The grip coordinates of the tool are determined by obtaining the posture, and the wrist trajectory of the manipulator 1 is automatically calculated and displayed.

In the present embodiment, with the user selecting a trajectory, for example, by operating the mouse, the menu "Edit" in the menu bar 18 is selected by pressing the mouse button and the mouse button is pressed. If you click the command "Add tool change path" in the menu as it is, the wrist of the manipulator 1 moves to the tool changer created based on the predetermined data structure of the tool changer, and the tool is changed. The trajectory of a series of motions until returning to the original teaching point is postured, added to the original trajectory, and displayed.

In this embodiment, the attribute of each teaching point is given the name of the tool held when the teaching point is passed. The following processing is performed by the above-mentioned "tool change trajectory addition" command.

FIG. 7 is a flow chart showing the tool change trajectory adding process of the embodiment of the present invention.

Step 70: The user selects a trajectory on the computer display screen 16.

Step 71: Computer display screen 16
Select "Edit" from the menu bar 18 of and then select the "Add Tool Change Trajectory" command.

Step 72: Here, the processing is selected according to the tool name attribute of the teaching point before and after the tool replacement trajectory addition position such as the presence or absence of the tool before the addition position and the presence or absence of the tool after the addition position. If there is no tool before the additional position and a new tool is added, the process proceeds to step 79, and if there is a tool before the additional position and the tool is removed, the process proceeds to step 80.

Step 73: When the tool is replaced, a trajectory from the final teaching point to the tool removal approach point is generated.

Step 74: Computer display screen 16
Generate a trajectory to a more detached point.

Step 75: Generate a trajectory to the detaching / separating point.

Step 76: Generate a trajectory to the adhesion approach point.

Step 77: Generate a trajectory to the mounting point of the tool.

Step 78: Generate a robot trajectory to the attachment / detachment point. Control goes to step 83.

Step 79: When mounting a tool,
A trajectory from the final teaching point to the mounting approach point is generated. Control goes to step 83. Step 80: When removing the tool, generate a trajectory from the final teaching point to the tool removal approach point.

Step 81: Generate a trajectory to the tool removal point.

Step 82: Removal A trajectory is generated to the departure point.

Step 83: Generate a trajectory to the current teaching point.

In the above flow chart, there are three methods according to the tool name attribute of the teaching point before and after the position where the tool change trajectory is added. When there is no tool before the position where the tool is added, the tool used at the later teaching point is grasped by the tool changer and returned to the original teaching point position. In this embodiment, the tool changer stores data such as tool attachment point, attachment approach point, attachment detachment point, detachment point, detachment approach point, detachment detachment point position and wrist posture for each tool held by the tool changer. ing. The trajectory editing system generates a tool exchange trajectory based on the flowchart shown in FIG. 7, adds it to the robot trajectory, and displays it on the display device.

[0081]

As described above, according to the present invention, the user selects a command for defining a tool and displays the contact point coordinates that represent both the position of the contact point and the tool posture with respect to the gripping coordinates of the tool at the same time. It can be easily input as a parameter for defining the shape of the tool, and the captured parameter can be displayed graphically as three-dimensional information using a graphical user interface, so that the spatial positions of the contact point and the grip point on the tool can be determined. It becomes easier to understand the relationship, and the time and effort of the user to enter accurate information can be greatly reduced.

Further, by recognizing the contact point trajectory based on the shape information of the work, the local coordinate system is uniquely set at the contact point based on the contact point and the shape around the contact point and the traveling direction of the contact point trajectory. By generating a local coordinate system to be defined and defining the spatial positional relationship between the contact point and the grip point of the tool by the tool definition, the wrist trajectory of the robot can be automatically generated.

Further, a tool model and a tool changer model are held for tool exchange, and a trajectory is generated on the basis of these pieces of information, so that a tool including the tool type information in the trajectory information can be used up to a position where the tool changes. It is possible to automatically add a path for the tool changer to move, change tools, and return.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the first principle of the present invention.

FIG. 2 is a diagram illustrating a second principle of the present invention.

FIG. 3 is a configuration diagram of a computer system and a robot system according to an embodiment of the present invention.

FIG. 4 is a diagram for explaining the operation of the embodiment of the present invention.

FIG. 5 is a diagram showing an example of a tool definition window according to an embodiment of the present invention.

FIG. 6 is a flowchart of contact coordinate processing according to an embodiment of the present invention.

FIG. 7 is a flowchart of a tool change trajectory adding process according to an embodiment of the present invention.

[Explanation of symbols]

 1 Robot Manipulator 2 Sensor Fixture 3 Laser Range Scanner 4 Irradiation Laser Light 5 Computer System 6 Display 7 Keyboard 8 Keyboard Connection Cable 9 Mouse 10 Mouse Connection Cable 11 Processing Device 12 Manipulator Controller 13 Computer Connection Cable 14 Work 15 Machining worktable 16 Computer display screen 17 Main display window 18 Menu bar 19 Pulldown menu 20 Mouse cursor 21 Coordinate icon 23 Tool edit subwindow 24 Frame edit subwindow 25 Shape edit subwindow 26 Select button 27 Select button group 28 Frame information 29 Contact point trajectory 30 Robot trajectory 31 Attribute designation / display frame 32 Up / down button 33 Acceleration type up / down button 3 4 Control bar 35 Slider 38 Dialog window frame 51 Tool gripping coordinate 52 Tool working coordinate 53 Tool definition window

Claims (3)

[Claims] 1. A method for creating a robot trajectory using a computer system having a display device, comprising visually displaying a three-dimensional positional relationship between a gripping point of a tool and an action point in the display device of the computer system. An image is displayed, a three-dimensional positional relationship is changed based on an arbitrary change operation for the three-dimensional positional relationship designated by the user on the screen of the display device, and a visual image is displayed to display the three-dimensional positional relationship. A method for teaching a robot trajectory, which comprises generating a robot trajectory from a contact point trajectory based on the method. 2. A position on the robot trajectory in which the tool held by the robot in the robot trajectory information including tool information is to be replaced is detected, and the trajectory to the position of the tool changer at the detected position, and the tool changer 5. A track to the position where the tool is replaced and returned is added, and a visual image of the added track is displayed.
A method for teaching a robot trajectory as described. 3. A method of creating a trajectory of a robot using a computer system having a shape input device for inputting the shape of a work and a display device, comprising: a tool of the robot on the work in the order of the robot trajectory. The local shape information including the locus of the contact point of the tool is input, and the accurate position of the contact point to be touched by the tool is recognized as the connection position information based on the local shape information. A local coordinate system at the contact point position with the tool on the work is generated based on the traveling direction and the local shape information of the work, and the local shape information of the work input in the display device of the computer system. And the contact point trajectory information of the tool and the local coordinates at the contact point position are simultaneously converted into a visual image and displayed, and a change is made to the robot trajectory information specified on the display screen. Edit based on the operation, a method for teaching a robot trajectory and displaying a visual image of the robot path information.