Patent
1991-08-19
1994-05-17
MacDonald, Allen R.
395 82, 395 97, G06F 1500, G05B 1900, B25J 906
Patent
active
053135636
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of controlling a robot with a supplementary axis, whereby robot is controlled by following the supplementary axis, and more particularly, to a method of controlling a robot with a supplementary axis, whereby the robot is automatically moved in response to a manual jog-run of the supplementary axis.
2. Description of the Related Art
In a welding robot or the like, a table on which a workpiece is fixed is designed to rotate or move in a direction perpendicular to such a rotation. The table is controlled by a supplementary axis control circuit incorporated in a robot control unit. This facilitates the control of the posture of the robot when performing a welding or other machining.
If, however, the table is jogged by the hand, the position and posture of the torch of the welding robot and the work on the table are changed. Therefore, to maintain a constant position and posture, it is necessary to give an instruction to adjust the position and posture of an arm of the robot; and posture. Such an instruction, however, cannot be easily given in a conventional robot, as it requires much time and a complicated teaching procedure.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above problem and provide a method of controlling a robot with a supplementary axis, to thereby cause the robot to automatically follow a manual feed of the supplementary axis.
To solve the aforementioned problem, the present invention provides a method of controlling a robot with a supplementary axis, to thereby control the tool center point (TCP) of the robot through the supplementary axis. According to the present invention, the supplementary axis is manually fed, a coordinate position of the supplementary axis is read, coordinates and a posture of the tool center point are determined so that the relative position and posture of the supplementary axis coincide with said tool center point of the robot, and the tool center point is then moved accordingly.
When the supplementary axis, such as a table, is moved by hand, the resulting new coordinate position is read through a supplementary axis control circuit, a position and coordinates of the tool center point that correspond to such a movement are determined by a microprocessor which controls the robot, and the arm of the robot is positioned in accordance with the new position and coordinates of the tool center point. This makes it possible to maintain a constant position and posture relationship between the supplementary axis, such as a table, and the tool center point .
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart of a method of controlling a robot with a supplementary axis according to the present invention;
FIG. 2 is a configuration diagram of a robot system for implementing the present invention; and
FIG. 3 is a diagram which shows the relationship between the tool center point (TCP) and the coordinate system of the supplementary axis.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An embodiment of the present invention will now be described with reference to the drawings.
FIG. 2 is a configuration diagram of a robot system according to a first embodiment of the invention, wherein a torch 3 is installed on the end of a wrist 2 of a robot 1. A table 5 is controlled by a supplementary axis control circuit 8 in a robot control unit 7. The table 5 is controlled to rotate and move in a direction perpendicular to the rotation. A workpiece 6 is fixed on the table 5.
The table 5 is rotated or manually jog-run in a vertical direction through a control panel, not shown in the drawing. A microprocessor in the robot control unit 7 reads the coordinates of the table 5 through the supplementary axis control circuit 8 and controls the robot 1 such that the positional relationship between the end of the torch 3 and the workpiece 6 remains unchanged.
FIG. 3 shows the relationship between the tool center point (TCP) and the coordinate system of the supplementary axis.
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patent: 4836742 (1989-06-01), Ishiguro et al.
patent: 5020001 (1991-05-01), Yamamoto et al.
Richard Weston, Robot workplaces, Jun. 1984, vol. 8, No. 5, pp. 245-248.
Fanuc Ltd.
MacDonald Allen R.
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