JPH01175608A - Method for generating teaching data of robot - Google Patents

Abstract

PURPOSE:To facilitate the generation of teaching data with respect to the change of end effecter by calculating state data of respective joints from a specified coordinate transformation matrix. CONSTITUTION:A robot controller 20 fetching size data of a welding torch 46 which is inputted from a teaching box and which has been altered, and obtains the transformation matrix in the case of using the altered welding torch 46 with setting the position and attitude of the operation point TCP of the welding torch 46 which has been altered equal to those of the operation point TCP of the welding torch before it is altered. When the transformation matrix is inverted, a subsequent angle in the joints when respective coordinate systems O1-O6 are set can be obtained, and a subsequent pulse with respect to the altered welding torch 46 is obtained from the angle, whereby the pulse is stored in a storage means as corrected teaching data. Thus, teaching again for data correction is eliminated, and the correction of data is facilitated.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for creating teaching data for a robot, and in particular, when changing the end effector of a robot, the dimensions of the end effector before and after the change are determined. The present invention relates to a method for creating teaching data for a robot that allows the teaching data to be easily modified based on the dimensions of an end effector.

[Background of the Invention] For example, when performing a predetermined work on a work using an industrial robot, it is necessary to move an end effector attached to the tip of the robot along a predetermined path. In this case, the route is generally taught by a teaching box. Here, the teaching box used for teaching the robot is equipped with input means for selecting command values for driving each joint of the robot, a coordinate system as a reference for teaching, or a setting means for setting the operating speed of the robot. The operator teaches the robot by operating these means according to predetermined specifications.

By the way, in such industrial robots, there are cases where it is requested to change the end effector during work. For example, if there is a partial change in the shape of a workpiece on a line where a welding robot performs a predetermined welding operation on the workpiece, the end effector may be changed in size, shape, etc. to avoid interference between the end effector and the workpiece. It becomes necessary to exchange it for something.

However, when the end effector is replaced, there is a risk that the position of the working point of the end effector relative to the workpiece may shift. Therefore, the operator usually has to perform teaching again after replacing the end effector of the robot. As a result, it has been pointed out that not only an excessive burden is imposed on the operator, but also a long time is required for the teaching work, causing a reduction in the operating rate of the production line.

[Object of the Invention] The present invention has been made to overcome the above-mentioned disadvantages, and when replacing the end effector of a robot, the dimensional data of the end effector before the change and the dimensional data of the end effector after the change are exchanged. By determining the coordinate transformation matrix between the joints that make up the robot based on the above, and calculating the state data of each joint from this coordinate transformation matrix, it is easy to create teaching data for changing the end effector, and the robot operation The purpose of this invention is to provide a method for creating robot teaching data that can contribute to improving the teaching rate.

[Means for Achieving the Object] In order to achieve the above-mentioned object, the present invention provides a method for changing the end effector of an articulated robot that is driven according to teaching data, based on state data of each joint constituting the articulated robot. , calculate the coordinate transformation matrix between each joint, calculate the position of the work point by the end effector based on the coordinate transformation matrix and the dimensional data of the end effector before the change, and then calculate the position of the work point by the end effector after the change. A new coordinate transformation matrix between each joint is determined so that the position and orientation of the work point match the position and orientation of the work point by the end effector before the change, and the new state of each joint is determined from the new coordinate transformation matrix. It is characterized by calculating data.

[Embodiments] Next, preferred embodiments of the robot teaching data creation method according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates a welding system to which the robot teaching data creation method according to the present embodiment is applied, and in this welding system 10, a sequencer 1
Arc welding robot 1 based on sequence control by 2
4 is driven, and a predetermined welding operation is performed on the workpiece 15 positioned on the jig table 17 by the clamping device W16.

In this case, the arc welding robot 14 is taught its operation by the teaching box 18, and is driven and controlled by the hydraulic unit 22 and the welding controller 24 via the robot controller 20.

The arc welding robot 14 is installed on a base 26, and the moving part 28 is moved in the direction of the arrow with respect to the base 26 by a hydraulic motor 30, and the rotating part 32 is moved to the moving part 28 by a hydraulic motor 34. On the other hand, it is configured to be able to turn in the direction of the arrow. Further, one end portion of an arm member 36 is pivotally attached to the rotating portion 32, and this arm member 36 is attached to the rotating portion 32.
It is configured to be movable up and down in the direction of the arrow by a hydraulic cylinder 38 attached to. On the other hand, a mounting member 42 having a hydraulic motor 40 is attached to the other end of the arm member 36, and a welding torch 46 as an end effector is connected to the mounting member 42 via a hydraulic motor 44. In this case, the welding torch 46 is centered around the hydraulic motor 44 and
0, the hydraulic motor 44 rotates in the direction of the arrow.
It is configured to be rotatable in the direction of the arrow. The hydraulic unit 22 described above drives and controls the hydraulic motors 30, 34, 40 and 44 and the hydraulic cylinder 38 that constitute the arc welding robot 14. Further, the welding controller 24 achieves welding current control between the welding torch 46 and the workpiece 15.

Here, with respect to the arc welding robot 14, the base coordinate system 0° fixed to the base 26 and the workpiece 1 of the welding torch 46 are
Hand coordinate system 01 fixed at work point TC, P for 5
and coordinate systems 01 to 0. for each joint of the arc welding robot 14. Define.

The base coordinate system 0° is orthogonal to Xo, Yo, and Zo.

It consists of 3 axes, and the rotation direction around each axis is A0, Bo,
Co. Hand coordinate system 0. consists of three orthogonal axes X, , Y, , Z, and the rotation direction around each axis is A, , , respectively.
Let B, ,C, be. The coordinate system 01 is a coordinate system that is displaced with respect to the base coordinate system 0° by the hydraulic motor 30, and the coordinate system 0□ is a coordinate system that is rotated with respect to the coordinate system 01 by the hydraulic motor 34, and the coordinate system 0. is set to coordinate system 0 by the hydraulic cylinder 38! It is a coordinate system that rotates with respect to

Also, the coordinate system 04 is the coordinate system 0. This is a coordinate system fixed to the arc welding robot 14, and was added to explain the arc welding robot 14 as a 6-axis robot. Furthermore, the coordinate system 0. is a coordinate system that rotates with respect to the coordinate system 04 by the hydraulic motor 40, and the coordinate system O5 is a coordinate system that rotates with respect to the coordinate system Os by the hydraulic motor 44.

On the other hand, the teaching box 18 is configured as shown in FIG. That is, the teaching box 18 basically includes a main body section 52 that performs teaching etc. to the arc welding robot 14, and a display section 54 that displays the operating method of the teaching box 18 and the like.

The main body 52 is connected to the robot controller 20 via a connection cable 55, and on the top thereof there is a mode changeover switch 56 for switching between a teach mode, a play mode, etc., which will be described later, and a mode switch 56 for manually operating the arc welding robot 14. A joystick 58 for controlling the arc welding robot 14, a numeric keypad 60 for selecting functions, inputting data, etc., and an emergency stop button 62 for stopping the operation of the arc welding robot 14 in an emergency are provided. In this case, joystick 58
is configured to be able to tilt in the directions of arrows α and β and to rotate in the direction of arrow γ, and the correspondence between the tilting direction or rotation direction and the driving direction of the arc welding robot 14 is set by the numeric keypad 60. Ru. Further, the operating speed of the arc welding robot 14 is set by the tilt angle or rotation angle of the joystick 58. In addition,
An operation switch 64 is provided at the tip of the joystick 58, and by pressing the operation switch 64, the arc welding robot 14 becomes operable.

The main body portion 52 includes a pair of arm members 6 that protrude diagonally upward.
6a, 66b, and these arm members 66a
, 66b through mounting screws 68a, 68b, the display section 54 is rotatably mounted in the direction of arrow β. In this case, the display section 54 has an LCD display 70, on which the operating method of the teaching box 18 selected by the mode changeover switch 56 and the numeric keypad 60 is displayed.

The welding system to which the robot teaching data creation method according to the present embodiment is applied is basically configured as described above. Next, a teaching method using this system will be described.

First, the power of the teaching pendant 18 is turned on. In this case, a main menu screen 80 shown in FIG. 3 is displayed on the LCD display 70 of the teaching box 18. In this main menu screen 80, rTE
ACH is a teaching mode in which the arc welding robot 14 is taught using the joystick 58, and PLAYJ is a play mode in which desired teaching data is called up using a keyboard (not shown) of the robot controller 2o and the arc welding robot 14 is operated. Also, rAUTo.

is an auto mode in which the play mode described above is automatically executed based on a request from the sequencer 12, etc., and the actual welding work of the workpiece 15 by the arc welding robot 14 is performed in this auto mode.

rEDITJ is an editing mode for editing (stereoscopic shift, copying, etc.) the teaching data stored in the teaching box 18, and "PARAJ is a parameter setting mode for setting parameters such as the dimensions of the welding torch 46 in the arc welding robot 1-14. mode.

Therefore, the operator presses the mode selector switch 56 [5].
The parameter setting mode is selected from the main menu screen 80 by setting the parameter to the position .

Then, the dimensional data of the welding torch 46 is input using the numeric keypad 60.

Next, when the operator selects the teach mode from the main menu screen 80 and sets the mode selector switch 56 to the [1] position, the teach mode menu screen 82 shown in FIG. 4 is displayed on the LCD display 70.

In this case, rJOINT 123J is a mode in which the hydraulic motors 30, 34 and hydraulic cylinders 38 that constitute the arc welding robot 14 are driven in response to the movement of the joystick 58 in the arrow α, β, and T directions. Further, "rJOrNT 456" is a mode in which the hydraulic motors 40 and 44 are driven in response to the movement of the joystick 58 in the directions of arrows α and β. rBASE
YZJ is a mode in which the working point TCP of the welding torch 46 moves in the Xo, Yo, and Zo force directions of the base coordinate system O0 with the base 26 as a reference in response to the operation of the joystick 58. Furthermore, rBASE ABCJ indicates that the working point TCP of the welding torch 46 with respect to the operation of the joystick 58 is Xo, Yo, Zo of the base coordinate system 0°.
This is a mode in which it rotates around A, , B, and C0 directions. On the other hand, "HAND XYZJ is joystick 5.
8, the working point TCP of the welding torch 46 is X of the hand coordinate system 08 with reference to the working point TCP,
This is a mode for moving in the Y, , and Z directions. Similarly, r
HAND ABCJ is the working point TCP of welding torch 46
is the hand coordinate system 0. Around X, , y, , z, A@,
This is a mode of rotation in the B, , and C directions. rBASE
MDI and rHAND MDIJ are modes in which the working point TCP of the welding torch 46 moves based on teaching data input with reference to the base coordinate system O0 or the hand coordinate system 0°. And rME
MORI ZE uses the current state of the arc welding robot 14 as teaching data to the robot controller 2.
This shows a mode for importing data into storage means (not shown) of No. 0.

Therefore, for example, when [3] is input from the numeric keypad 60, the mode "rBAsE XYZ" is selected from the teach mode. Next, while pressing the operation switch 64, the operator tilts or rotates the joystick 58 by a predetermined amount in the directions of arrows α, β, and γ. in this case,
Data regarding the tilt direction, rotation direction, tilt angle, and rotation angle of the joystick 58 are transferred to the robot controller 20 via the connection cable 55. The robot controller 20 generates a pulse signal corresponding to the movement amount of each coordinate system OI to 06 of the arc welding robot 14 based on the selected rBASE XYZ mode from the above data and outputs it to the hydraulic unit 22. The hydraulic unit 22 moves the working point TCP of the welding torch 46 in the arc welding robot 14 to a desired welding position on the workpiece 15 according to the base coordinate system 0° based on the pulse signal. In this case, the work point TCP is moved in the 70 direction by tilting the joystick 58 in the arrow α direction, moved in the X0 direction by tilting the joystick 58 in the arrow β direction, and moved in the Y0 direction by rotating it in the arrow γ direction. respectively.

On the other hand, when the operator confirms that the working point TCP of the welding torch 46 has moved to the desired welding position on the workpiece 15 and that the welding torch 46 has assumed the desired attitude relative to the workpiece 15 by the operation described below, the teaching box A teaching data storage command is input using the 18 numeric keys 60. In this case, when O and ■ on the numeric keypad 60 are pressed according to the teach mode menu screen 82 shown in FIG. be remembered. By repeating the above operations for each desired welding position, the teaching operation of the arc welding robot 14 is completed.

When the teaching work of the arc welding robot 14 is completed, the operator displays the LCD of the teaching box 18.
The screen on the display 70 is returned to the main menu screen 80 shown in FIG. Next, set the mode selector switch 56 to [2].
] is set to the play mode, the arc welding robot 14 is made to perform the Braver Neck operation, and the teaching data is confirmed.

Next, arc welding robot 1 based on the teaching data
When the operation check in step 4 is completed, the operator returns the screen of the LCD display 70 to the main menu screen 80, and then selects [3] on the numeric keypad 60 to enter the auto mode. In this case, the arc welding robot 14 is connected to the sequencer 1
A desired welding operation is performed on the workpiece 15 based on the teaching data output from the robot controller 20 under the control of the robot controller 20.

By the way, if there is a partial change in the shape of the workpiece 15 to be welded by the arc welding robot 14, the welding torch 46 or other parts of the arc welding robot 14 may interfere with the workpiece 15. be. In such a case, it becomes necessary to change the welding torch 46 to another welding torch 46 with different dimensions. Therefore, in this embodiment, the teaching data is corrected by selecting the parameter setting mode on the main menu screen 80 and inputting the changed welding torch dimension data. Therefore, a method for creating teaching data related to changing the welding torch will be explained based on the flowchart shown in FIG.

First, the operator displays the LCD of the teaching pendant 18.
Main menu screen 80 displayed on display 70
Select the mode rPARA from , and enter the changed welding torch dimension data using the numeric keypad 60.

On the other hand, the robot controller 20 receives the current pulse Pz (i=1.2, . . . 6
), and from this pulse P, the adjacent coordinate system 01
The current angle ri of each joint with respect to 06 is determined as (i=1.2, . . . 6) (STPI). Here, the k-th coordinate system is 01
These are parameters related to the resolution and reduction ratio of the potentiometer. kZi is an offset amount for expressing the pulse pt obtained by the potentiometer as an increase/decrease with respect to the reference midpoint when a reference midpoint is set for the range of motion of the joint in the coordinate system O5.

Also, k3. is a parameter for converting an angle (deg) into radians. Note that in this embodiment, the coordinate system is 0
4 is the coordinate system 0. Since the pulse P4 is fixed to
Set to O.

Next, a transformation matrix T is calculated from the current angle ri calculated based on equation (1) (SrF2).

In this case, the transformation matrix T sets the position and orientation of the coordinate system O with respect to the base coordinate system O0, and also each component of the transformation matrix T. (m=1.2.3, n=L 2.3
．． 4) As (i=1.2,...6)...
- It is set as in (2). Here, the transformation matrix T is T
'E Ck i b )...(
3), the current position C of the work point TCP in the welding torch 46 before the change is calculated as follows using the transformation matrix T (SrF2). Note that A is the transformation matrix T
b is the component of the left side 4 rows and 3 columns of the transformation matrix T, and b is the right side 4
The components in row and column 1 are shown.

Further, h is a vector that includes dimensional data of the welding torch 46 before change and indicates the amount of offset of the work point TCP with respect to the coordinate system 06. In this case, h is the component in the Xo, Y, , Z direction with respect to the base coordinate system 0° as h+, h
As z and hs, it is defined as follows.

Next, the robot controller 20 determines whether there is an end effector change command from the teaching box 18 (5TP4), and if there is no change, the current pulse P is held as is (SrF5).

On the other hand, when the parameter setting mode is selected in the teaching box 18, the robot throat controller 20 takes in the data input from the numeric keypad 60 as the changed dimension data of the welding torch (SrF6). Here, this dimensional data is divided into components hl', ht', h
3' as a vector h'. In this case, the coordinate system when using the changed welding torch is 0. What is the transformation matrix T' for? ' E [A", b ') ... (7
). The position and posture of the working point TCP of the welding torch after the change are the working point TCP of the welding torch 46 before the change.
It must be equal to the position and orientation of
c...(8) A'=A...(9) relationship is obtained. Therefore, (4), (8) and (9)
The formula% is the formula%. As a result, (from the force equation, the transformation matrix T′ is T”
' = (Ai A' ・(h, -ha') ten b )
...0]) (SrF2).

Therefore, by inversely transforming this transformation matrix T', each coordinate system o
The next angle r%(i
=1.2,...6) can be obtained (SrF8
). As a result, the next pulse PI' for the welding torch after changing the angle r,' is (i=1.2,...6)...Q2+
It is found as follows (SrF9).

Next, the robot controller 20 stores the pulse Pi' obtained in step 9 in a storage means (not shown) as modified teaching data. By repeating the above process for all teaching points, teaching data related to the changed welding torch is created.

[Effects of the Invention] As described above, according to the present invention, when changing the end effector of a robot, the teaching is corrected based on the dimensional data of the end effector before the change and the dimensional data of the end effector after the change. Is going. In this case, there is no need to perform teaching again to correct the data.
Therefore, the work is reduced and data correction becomes extremely easy. Furthermore, since it does not take a long time to create data, the robot has very little impact on the manufacturing line to which it is applied, and can contribute to improving the operating rate.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a welding system to which the robot teaching data creation method according to the present invention is applied; FIG. 2 is a perspective view of the configuration of a teaching box in the welding system shown in FIG. 1; FIGS. The figure is an explanatory diagram of each menu screen displayed on the teaching box shown in FIG. 2, and FIG. 5 is a flowchart showing the procedure of the robot teaching data creation method according to the present invention. 10... Welding system 12... Sequencer 1
4... Arc welding robot 18... Teaching box 20... Robot controller 22... Hydraulic unit 24... Welding controller 52... Main body part 54... Display part 5
6...Mode selector switch 58...Joystick 60...Numeric keypad 62
...Emergency stop button 64...Operation switch 70
...LCD display FIG, 5

Claims (1)

[Claims] (1) When changing the end effector of an articulated robot driven according to teaching data, a coordinate transformation matrix between each joint is determined from the state data of each joint that makes up the articulated robot, and the coordinate transformation matrix is changed to the coordinate transformation matrix. The position of the work point by the end effector is calculated based on the dimensional data of the previous end effector, and then the position and posture of the work point by the end effector after the change are the position of the work point by the end effector before the change. and a new coordinate transformation matrix between each joint so as to match the posture, and new state data of each joint is calculated from the new coordinate transformation matrix.