JP2001312305A - Tool control method for robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling a robot tool by which a user can independently jog and aiming angle or tilt angle to a welding line and can simplify teaching work. SOLUTION: A first coordinate system is operated by rotating a tool coordinate system so that a moving route direction operated from a position taught concerning at least two teaching points on a moving route can be matched with arbitrary one axis of a tool coordinate system concerning one arbitrary teaching point, an axis is operated by projecting an axis expressing the tool direction of the tool coordinate system of the teaching point on a plane orthogonal to the moving route direction, and a second coordinate system is provided by rotating the first coordinate system around the moving route direction so that this axis can be matched with one arbitrary axis except for the axis matched in the moving route direction of the first coordinate system. Then, a present third coordinate system is operated by using a transformation matrix for transforming the tool coordinate system to the second coordinate system and the tool coordinate system, and a tool attitude on the second coordinate system is displayed from the second coordinate system and the present third coordinate system by controlling parallel movement and rotary movement to axes more than one arbitrary axis of the third coordinate system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool attitude control method for an industrial robot (hereinafter, referred to as a robot), and more particularly, to a method of creating a coordinate system having coordinate axes coincident with the direction of movement of a robot path. And a method for controlling a tool posture of a robot based on the coordinate system.

[0002]

2. Description of the Related Art When teaching a robot, there are applications in which the posture between a tool and a work object is important. For example, when a robot is applied to arc welding, the position of the tool greatly affects welding quality. In order to solve this, in the method disclosed in Japanese Patent Application Laid-Open No. 58-188566, the welding line direction is calculated, and the angle of inclination and the target angle of the welding torch are input as numerical values. Further, in the robot jog operation method disclosed in International Publication W097 / 06473, a method for easily operating the tool posture of the robot by jog operation is provided.

[0003]

However, Japanese Patent Application Laid-Open No.
In the method disclosed in Japanese Patent No. 188566, it is necessary to set the surface of the work by some method in order to input the posture data of the tool numerically. This is good when the welding member has a simple shape, but when the welding line is complicated, such a method requires a great deal of teaching time to teach the surface of the work. In addition, interference between the tool and the welding member or the jig that fixes it cannot be confirmed unless the robot is moved to that position, and after teaching the position, input the posture angle of the tool. Then, the operator needs to confirm the teaching position of the robot again.
In order to change the tool at a certain position, it is necessary to input an angle based on the welding line, move the robot to that position again, and check it. Required a very long teaching time. In addition, in the robot jog operation method disclosed in International Publication W097 / 06473, the jog operation is possible, but the posture of the tool at that position cannot be expressed numerically. For example, the operator cannot recognize the current angles of the aiming angle and the inclination angle, and the welding quality ultimately greatly depends on the skill of the operator. Therefore, the present invention enables the user to independently perform the jog operation of the aiming angle and the inclination angle with respect to the welding line, simplify the teaching work, and display the current tool posture from the reference tool posture. It is an object of the present invention to provide a control method of a robot tool capable of managing welding quality regardless of the above.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a control of a tool attached to a wrist of an articulated robot having a plurality of axes and rotating each axis. In the method, a direction of a movement path is calculated from positions taught for at least two teaching points on the movement path, and any one axis of a tool coordinate system of any one teaching point of the teaching point is calculated. A first coordinate system obtained by rotating the tool coordinate system so as to match the direction of the movement path is calculated, and an axis expressing the tool direction of the tool coordinate system of the teaching point is projected on a plane orthogonal to the direction of the movement path. An axis is calculated, and the first coordinate system is rotated around the direction of the movement path so that any one axis other than the axis matched with the path movement direction of the first coordinate system matches the projected axis. Memorized as a coordinate system, whether it is a tool coordinate system A conversion matrix to be converted to the second coordinate system is obtained and stored, and a current third coordinate system is calculated based on the tool coordinate system and the conversion matrix, and translation is performed on any one or more axes of the third coordinate system. The movement and the rotation are controlled, and the tool posture in the second coordinate system is displayed from the second coordinate system and the current third coordinate system. It also has multiple axes,
In a control method of a tool attached to a wrist of an articulated robot configured to rotate each axis, a control device calculates a movement path direction from positions taught at least two teaching points on the movement path. The tool coordinate system is rotated so that any one axis of the tool coordinate system of any one of the taught points coincides with the direction of the movement path.
Calculates the coordinate system, calculates an axis that projects an axis representing the tool direction of the tool coordinate system of the teaching point on a plane orthogonal to the moving path direction, and matches the axis with the path moving direction of the first coordinate system. The first coordinate system is rotated around the direction of the movement path so that any one axis other than the set axis and the projected axis coincide with each other, stored as a second coordinate system, and moved from the tool coordinate system to the second coordinate system. A conversion matrix to be converted is obtained and stored, and a rotation angle and a translational movement distance of one or more arbitrary axes in the second coordinate system are input from the teaching device, and the second coordinate system is converted from the second coordinate system based on the input numerical values. The three coordinate systems are calculated, the tool coordinate system of the robot is calculated from the third coordinate system and the transformation matrix, and the robot is translated and rotated to the input posture.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart of an embodiment of the present invention. Hereinafter, each step will be specifically described. Step 1: path direction of movement of the shaft and the tool coordinate system shown in FIG. _{2 (a) (X T,} Y T, Z T) to match the X-axis X _T of, rotating the tool coordinate system. This rotated coordinate system is defined as F _A (X _A , Y _A , Z _A ). A schematic diagram is shown in FIG. In the figure, reference numeral 10 denotes a tool (welding torch). Step 2: Create a plane 1 perpendicular to the X-axis X _A of the coordinate system F _A. FIG. 3 shows a schematic diagram of this. Step 3: An axis 2 is created by projecting the Z axis of the current tool coordinate system on the plane 1 obtained in step 2 (FIG. 4). To match the coordinate system F _A to the shaft 2, to rotate the coordinate system F _A around the X-axis. This coordinate system is expressed as F _B (X _B , Y _B , Z _B )
And stored in the robot controller. Step 4: storing an angle of Z-axis Z _B and a coordinate system F _B of the tool coordinate system α (see FIG. 5) to the robot controller. Step 5: calculates the transformation matrix T for converting from the tool coordinate system to the coordinate system F _B, and stores. Step 6: The user for the arbitrary axis in the coordinate system F _B, translation, rotation movement. From the transformation matrix T that are stored in the tool coordinate system and the step 5 at this point, to create a coordinate system F _C. And a coordinate system F _C and the coordinate system F _B, to calculate the x-axis rotational angle ΔROT_X coordinate system F _C against the coordinate system F _B (see FIG. 6). Step 7: An angle β between the Z axis Z _C of the tool coordinate system and the axis 2 of the coordinate system F _C is calculated in the same manner as in Step 4 (FIG. 7).
reference). Step 8: α previously stored in step 4
Then, the difference (ΔROT_Z) between β and β calculated in step 7 is calculated. In this step 8, the rotation angles (ΔROT_X, ΔROT_Z) calculated in steps 6 and 7 are displayed on a screen on the teaching device of the robot. By performing the steps 1 to 8 described above, the target angle and the advance angle of the torch that affect the welding quality can be quantified, so that the quality can be controlled regardless of the skill of the operator. According to the present invention, the target angle and the like are set simply and accurately by numerically inputting the target angle and the like in the coordinate system defined by the work plane and the welding line instead of the coordinate system fixed to the space. be able to.

[0006]

As described above, according to the present invention, the user can independently perform the jog operation for the aiming angle and the inclination angle with respect to the welding line, and the teaching operation becomes very simple. Further, since the current tool posture from the reference tool posture is displayed, there is an effect that the welding quality can be managed regardless of the skill of the operator.

[Brief description of the drawings]

FIG. 1 is a schematic flowchart of an embodiment of the present invention.

FIG. 2 is an explanatory view of the tool coordinate system and the coordinate system F _A.

FIG. 3 is an explanatory view of a plane 1;

FIG. 4 is a diagram in which a Z axis of a tool coordinate system is projected on a plane 1;

FIG. 5 is an explanatory diagram of α.

FIG. 6 is an explanatory diagram of ΔROT_X.

FIG. 7 is an explanatory diagram of β.

[Explanation of symbols]

 1 plane, 2 axes, 10 tools

Continued on the front page F term (reference) 3F059 AA05 BA02 BA10 BC07 CA06 DA02 DA08 FA03 FB01 FB05 FB26 FC13 FC14 5H269 AB33 BB03 CC09 QE19

Claims (2)

[Claims] 1. A method for controlling a tool attached to a wrist of an articulated robot having a plurality of axes and rotating each axis, the control device comprising: The first coordinate obtained by calculating the moving path direction from the taught position and rotating the tool coordinate system so that any one axis of the tool coordinate system of any one of the taught points coincides with the moving path direction. The teaching system calculates an axis by projecting an axis expressing the tool direction of the tool coordinate system of the teaching point on a plane orthogonal to the moving path direction, and makes the axis coincide with the path moving direction of the first coordinate system. The first coordinate system is rotated around the direction of the movement path so that any one axis other than the set axis coincides with the projected axis, stored as the second coordinate system, and converted from the tool coordinate system to the second coordinate system. Find and store the transformation matrix The third current by the coordinate system and the transformation matrix
Calculates the coordinate system, and translates and moves any one or more axes of the third coordinate system.
A tool control method for a robot, comprising: controlling a rotational movement; and displaying a tool posture in a second coordinate system from a second coordinate system and a current third coordinate system. 2. A method for controlling a tool attached to a wrist of an articulated robot having a plurality of axes and rotating each axis, the control device comprising: A movement path direction is calculated from the taught position, and the tool coordinate system is rotated so that any one axis of the tool coordinate system of any one of the taught points coincides with the movement path direction. Calculates a coordinate system, calculates an axis that projects an axis representing the tool direction of the tool coordinate system of the teaching point on a plane orthogonal to the moving path direction, and matches the path moving direction of the first coordinate system. The first coordinate system is rotated around the movement path direction so that any one axis other than the set axis and the projected axis coincide with each other, stored as a second coordinate system, and the tool coordinate system is moved from the tool coordinate system to the second coordinate system. Find and memorize the transformation matrix to be transformed, A rotation angle of at least one arbitrary axis in the second coordinate system and a translation distance are input from the device, and a third coordinate system is calculated from the second coordinate system based on the input numerical values. A tool control method for a robot, comprising calculating a tool coordinate system of the robot from the system and the transformation matrix, and translating and rotating the robot to the input posture.