JPH09311708A - Controller for industrial robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily set a user coordinate system by transforming the coordinates of a work coordinate system on the basis of a G code command, and newly setting the user coordinate system which has coordinate axes parallel to the normals of machined surfaces of a work by the machined surfaces and cutting the respective machined surfaces. SOLUTION: The robot controller which controls industrial robot reads the work coordinate system 7 and an NC program for machining a 1st and a 2nd machined surface out of a memory 10 and interprets it by an NC language execution part 12, transforms the coordinates of the work coordinate system by a coordinate transforming means 13 on the basis of the interpreted data, and sends data regarding the coordinate system set newly by the coordinate transformation, i.e., the user coordinate system to an actuator control part 14. Then, the actuator control part 14 generates data for driving respective articulation axis driving motors for operating the industrial robot.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device to which an optimum coordinate conversion method is applied in an industrial robot adapted to perform cutting using NC language.

[0002]

2. Description of the Related Art Conventionally, cutting including deburring has been performed by using a dedicated machine tool such as an NC (numerical control) machine tool. However, in recent years, with the increasing demand from users for flexible production lines, cutting using industrial robots has also been performed. Generally, the operation of an industrial robot is often taught by teaching, and it is necessary to be familiar with the robot language in order to perform this teaching. However, many users who have conventionally used NC machine tools are familiar with the NC language but do not have knowledge of the robot language. From these users, various workpieces to be cut are processed. In order to build a flexible production system that can handle
There has been an increasing demand for enabling C language. Then, in order to cope with this demand, various control methods and devices which enable the NC language have been developed.

The advantage of the cutting process using the industrial robot is that it can be easily applied to the cutting process other than the horizontal direction or the vertical direction with respect to the installation surface of the workpiece.
For example, in drilling using a three-axis controlled NC machine tool, the cutting direction (cutting direction) is generally limited to either the horizontal direction or the vertical direction with respect to the installation surface of the machine. The reason is that the gripping members of cutting tools such as drills used for drilling are often fixed either horizontally or vertically to the installation surface of the machine. However, in the case of an industrial robot, since the wrist shaft to which the cutting tool is attached can move in all directions, the cutting direction can be freely set with respect to the installation surface of the robot body.

When cutting is performed using an industrial robot, most of the cutting is performed in a vertical direction or a horizontal direction with respect to a processing surface. When controlling the cutting operation using the NC language, it is easier to create an NC language program if the cutting direction, that is, the cutting direction is parallel to any axis of the set three-axis orthogonal coordinate system. Generally, in an industrial robot, a Cartesian coordinate system is set so that any one axis of the three-axis Cartesian coordinate system is parallel to the axis perpendicular to the installation surface of the workpiece, and this is the work coordinate system. In this three-axis work coordinate system, it goes without saying that a plane formed by two axes other than the axis perpendicular to the installation surface of the workpiece is parallel to the installation surface of the workpiece.

When the shape of the work piece is a rectangular parallelepiped or a flat plate, the work surface is parallel to or perpendicular to the installation surface of the work piece. Therefore, a cut is made in the vertical direction or in the horizontal direction with respect to the work surface. For the machining to be performed, if the above-mentioned work coordinate system set for the installation surface of the workpiece is used as it is, the program block in the NC language program in which the movement command for cutting is described is the work coordinate system. Since it is only necessary to set a movement command for one of the three axes that is parallel to the cutting direction, it is easy to create an NC language program. However, in the case of a polyhedron whose work piece has an irregular shape, the work surface is neither parallel nor perpendicular to the work piece installation surface. If the work coordinate system is used as it is, the cutting direction will not be parallel to any one axis of this work coordinate system, and as a result, the program block in the NC language program in which the movement command is written has two axes. Alternatively, a three-axis movement command must be set, which causes a problem that the creation of an NC language program becomes complicated.

Further, when a two-axis or three-axis movement command is given, the NC control device must perform synchronous control of these two axes or three axes. However, in the case of cutting, two or more axes are synchronously controlled. It is generally well known that the machining accuracy of is worse than in the case of uniaxial control. For these reasons, in order to perform cutting processing on an irregular polyhedron in the industrial robot that can use the NC language, it is necessary to set a new coordinate system for each processing surface. The coordinate system newly set for each processing surface is called a user coordinate system.

As a method of setting the user coordinate system for each machining surface in the industrial robot, the method disclosed in Japanese Patent Publication No. 7-104712 has been used although it is not compatible with the NC language. That is, teaching is given to arbitrary 3 points set on the machined surface of the workpiece, position data of a plane including 3 points, that is, the machined surface is calculated from the position data of these 3 points, and the position of the machined surface is calculated. The coordinate system newly set based on the data, that is, the user coordinate system, is set so that any one axis of this user coordinate system is parallel to the machining line and the other two axes are on the machining surface. Is set to. This method uses the teaching work that has been often used in the past to set the motion path of the industrial robot, and thus is convenient for the user who is familiar with the operation of the industrial robot.

[0008]

However, as described above, the user who has been using the NC machine tool in the past is familiar with the operation of the NC machine tool, but the operation of the industrial robot, for example, teaching work. There are many things that I am not familiar with, so I will teach you 7-10
There is a problem that the method of No. 4712 cannot be easily implemented. In addition, it is possible to set arbitrary 3 points for each processing surface of the work piece and teach them each time by teaching work.
The method of -104712 is difficult to apply to a work piece having a plurality of work surfaces, a production line with many kinds of work pieces, or a production line in which the working specifications of the work piece are frequently changed. However, there is also a problem that when applied, it causes a significant decrease in processing efficiency. Further, since the positioning accuracy by the teaching work is generally lower than the cutting accuracy required by the NC processing, the position data of three points calculated by the teaching work and the machined surface calculated from the position data of these three points are used. Position data accuracy,
The reliability of the user coordinate system newly set based on the position data of the machined surface also becomes low, and as a result, the cutting accuracy of the workpiece machined by this user coordinate system also becomes low.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and can be easily set even by a user who is not familiar with teaching work, and a work piece having a plurality of work surfaces, It can be applied to a production line with many types of workpieces or a production line where the machining specifications of the workpieces are frequently changed, and a coordinate system setting method that guarantees cutting accuracy is also incorporated. Another object of the present invention is to provide a control device for an industrial robot.

[0010]

Therefore, the present invention is based on the NC
In an industrial robot capable of cutting a workpiece by a language program, coordinates designed to perform coordinate conversion based on a G code command specified on the NC language program with respect to a preset work coordinate system. By having the converting means, the coordinate converting means newly sets a user coordinate system having a coordinate axis parallel to the direction of the machined surface for each machined surface of the workpiece, and set for each machined surface. By providing a control device for an industrial robot, which is characterized in that each processing surface is cut based on a user coordinate system, the above-mentioned problems of the prior art are solved (claim 1).

With this configuration, in the robot controller of the industrial robot capable of cutting by the NC language program, by the coordinate conversion set by the G code command newly defined in the NC language program, It has become possible to easily and freely convert the preset work coordinate system to the user coordinate system according to the machining surface.

The G code command has, as its parameter,
It has a parallel movement amount of the coordinate origin with respect to the work coordinate system and a rotation movement amount of each coordinate axis, and a registration number of the user coordinate system newly set by the coordinate conversion means (claim 2). This facilitates the setting of coordinate conversion by the NC language program, and the coordinate system can be immediately changed by calling the registration number after the setting.

Further, as a configuration different from claim 2, the G code command has, as its parameter, a registration number for specifying any one of a plurality of preset coordinate systems and a designation by the registration number. A coordinate movement amount of the coordinate origin and a rotation movement amount of each coordinate axis with respect to the coordinate system are set (claim 3). This makes it easy to set the coordinate conversion by the NC language program and easily set a new coordinate system based on a plurality of preset coordinate systems.

Further, as a configuration different from the second and third aspects, the G code command includes, as its parameters, the parallel movement amount of the coordinate origin and the rotational movement amount of each coordinate axis with respect to the currently set coordinate system. (Claim 4). This makes it easy to set the coordinate conversion by the NC language program and easily set a new coordinate system based on the currently set coordinate system.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a system configuration of an industrial robot in one embodiment of the present invention, FIG. 2 is a diagram showing a positional relationship between a workpiece and a coordinate system, and FIG. 3 is a block of a robot controller. It is a figure which shows a figure. As shown in FIG. 1, a predetermined cutting process is performed on the workpiece 3 placed on the installation surface 22 of the processing table 21 by using the cutting tool 4 held by the tip of the industrial robot 1. I am supposed to do it. In the robot controller 2 connected to the industrial robot 1, it is possible to control the operation of the industrial robot 1 not only by the robot language program but also by the NC language program.

As shown in FIG. 2, the work piece 3 is assumed to be an infinite polyhedron other than a rectangular parallelepiped or a flat plate. The work piece 3 has a first processed surface 5 and a second processed surface 6, and
The processing surface 5 forms an angle α with the installation surface 22 of the processing table 21, and the second processing surface 6 forms an angle β with the installation surface 22 of the processing table 21. Since the bottom surface 23 of the work piece 3 is flush with the installation surface 22, the angles α and β may be the values set in the design specifications of the work piece 3 as they are. The three-axis work coordinate system 7 is preset so that its Z axis is parallel to the direction of the installation surface 22.

FIG. 3 is a block diagram showing the configuration of a robot controller 2 for controlling the industrial robot 1. Here, the industrial robot 1 uses the first processing surface 5 and the second processing surface 5 of the workpiece 3.
The procedure for processing the processed surface 6 will be described step by step. An NC program 11 for machining the work coordinate system 7, the first machining surface 5 and the second machining surface 6 is read from the memory 10 and interpreted by the NC language execution unit 12. Coordinate conversion of the work coordinate system is performed in the coordinate conversion means 13 based on the interpreted data, and data relating to the coordinate system newly set by the coordinate conversion, that is, the user coordinate system is transmitted to the actuator control unit 14, and the actuator control unit 14 is operated. Data for driving each joint axis drive motor for operating the industrial robot 1 is created.

The coordinate conversion flow of the work coordinate system processed by the coordinate conversion means 13 will be described in detail.
FIG. 4 shows N which defines the coordinate transformation newly set in the present invention.
It shows one form on the C program. G303
Is a G code command that defines coordinate conversion, and its parameters, X, Y, and Z are parallel movement amounts of the coordinate origin of the work coordinate system 7, U, V, and W are rotations of the coordinate axes of the work coordinate system 7. The movement amount, P indicates a user coordinate number as a registration number of a coordinate system newly set by this coordinate conversion, that is, a user coordinate system.

The user coordinate system 8 newly set when machining the first machining surface 5 has a Z axis parallel to the direction of the first machining surface 5 and a Z coordinate on the first machining surface 5. Is set to 0. From the positional relationship between the bottom surface 23 of the workpiece 3 and the first machining surface 5, which is obtained from the design specifications described in the design drawing of the workpiece 3, the translation amount of the coordinate origin and the rotation of each coordinate axis. Derive the amount of movement. If the parallel movement amount of the derived coordinate origin is (x1, y1, z1) and the rotation movement amount around the X axis is α, N relating to coordinate conversion in this case.
The C program is as shown in FIG. This NC program moves the coordinate origin of the work coordinate system 7 by the parallel movement amount (x1, y1, z1), and further rotates the X axis by the designated rotation movement amount α around the X axis. The first user coordinate system 8 designated by the coordinate number 7 is newly set.

Similarly, when the second machining surface 6 is machined, the user coordinate system 9 newly set has its Z axis parallel to the direction of the second machining surface 6 and on the second machining surface 6. The Z coordinate of is set to 0. From the positional relationship between the bottom surface 23 of the workpiece 3 and the second machining surface 6, which is obtained from the design specifications described in the design drawing of the workpiece 3, the amount of translation of the coordinate origin and the rotation of each coordinate axis. Derive the amount of movement. Assuming that the parallel movement amount of the derived coordinate origin is (x2, y2, z2) and the rotational movement amount around the X axis is β, the coordinate origin of the work coordinate system 7 is moved by the parallel movement amount (x2, y2, z2). Then, the second user coordinate system 9 in which the X axis is rotated by the designated rotational movement amount β around the X axis is newly set.

With the above processing, the first user coordinate system 8 having the Z-axis parallel to the machining surface line for the first machining surface 5 and the parallel to the machining surface line for the second machining surface 6 are obtained. A second user coordinate system 9 having different Z axes is set respectively. As a result, for example, in the machining program for machining the first machining surface 5 with the drill held by the tip of the industrial robot 1 to make a hole perpendicular to the machining surface, first the user coordinate number 7 is assigned to the first user. The setting for calling the coordinate system 8 is performed, then the setting for moving the drill to the sky above the first machining surface 5 by the X-axis and Y-axis moving commands, and finally the first by the Z-axis moving command. The setting for making a hole on the processing surface 5 is performed. In this machining program, a program block in the NC language program in which a movement command for performing cutting is described is a Z-axis parallel to the cutting direction among the three axes of the user coordinate system 8.
Since it is only necessary to set the axis movement command, the NC language program can be set easily.

In the above embodiment, as the parameters of the G code command, the parallel movement amount of the coordinate origin with respect to the preset work coordinate system and the rotation movement amount of each coordinate axis, and the user coordinates newly set by the coordinate conversion means. System registration number, and the user coordinate system for each machining surface with respect to the preset work coordinate system is set and registered in advance by executing the G code command to give the registration number. When processing each processing surface, the user coordinate system for each processing surface that has been set and registered is called by specifying the registration number.

However, there are some control devices in which a plurality of frequently used coordinate systems can be set in advance as a basic coordinate system. In this case, the user coordinate system to be newly set for each machining surface should be selected from any of these basic coordinate systems and set based on the amount of movement with respect to the selected basic coordinate system. May be convenient. Therefore, in this case, as a parameter of the G code command, a registration number that identifies any one of a plurality of preset coordinate systems, a translation amount of the coordinate origin with respect to the coordinate system designated by the registration number, and The G code command may be defined so as to have the rotational movement amount of each coordinate axis.

When creating an NC language program, it may be easier to create an NC language program if a new coordinate system is set based on the amount of movement with respect to the currently set coordinate system. Therefore, in this case, the G code command is defined so that it has the parallel movement amount of the coordinate origin with respect to the currently set coordinate system and the rotation movement amount of each coordinate axis as parameters of the G code command, and only the movement amount is thereby set. By designating, a new coordinate system may be set based on the currently set coordinate system.

[0025]

According to the present invention, in a control device for an industrial robot capable of cutting by an NC language program, arbitrary coordinate preset by a coordinate converting means set by the NC language program. Since it is now possible to easily and freely convert to a new coordinate system based on the system or the coordinate system before conversion, the workpiece with multiple machining surfaces, the production line with many types of workpieces, or the workpiece Even if the coordinate system needs to be changed frequently due to the difference in the machining surface, such as in a production line where the machining specifications are frequently changed, the NC language program can change the coordinate system in a short time. It became so.

Further, since it is possible to change the coordinate system by the NC language program, it is not necessary to set a new coordinate system by the conventional teaching work. Therefore, even a user who is not familiar with the teaching work can easily do so. You can now set the coordinate system. Furthermore, since the coordinate conversion means of the present invention is based on the machining specifications of the workpiece, the reliability of the converted coordinate shape is higher than that of the conventional coordinate conversion means based on the position data obtained by the teaching work. As a result, the cutting accuracy of the workpiece to be machined based on the converted coordinate shape is guaranteed.

[Brief description of drawings]

FIG. 1 is a diagram showing a system configuration of an industrial robot according to an embodiment of the present invention.

FIG. 2 is a diagram showing a positional relationship between a workpiece and each coordinate system according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a robot controller according to an embodiment of the present invention.

FIG. 4 is a diagram showing a form of an NC program that defines coordinate conversion according to an embodiment of the present invention.

FIG. 5 is a diagram showing an example of an NC program that defines coordinate conversion according to an embodiment of the present invention.

[Explanation of symbols]

 1 Industrial Robot 2 Robot Controller 3 Workpiece 5 First Machining Surface 6 Second Machining Surface 7 Work Coordinate System 8 First User Coordinate System 9 Second User Coordinate System 13 Coordinate Converting Means

Claims (4)

[Claims] 1. In an industrial robot capable of cutting a workpiece by an NC language program, coordinate conversion based on a G code command specified on the NC language program is performed on a preset work coordinate system. By having the coordinate conversion means configured to perform, a new user coordinate system having a coordinate axis parallel to the direction of the processing surface is newly set for each processing surface of the workpiece by the coordinate conversion means, and each processing A control device for an industrial robot, characterized in that each machining surface is cut based on a user coordinate system set for each surface. 2. The G code command according to claim 1, as its parameters, the parallel movement amount of the coordinate origin with respect to the work coordinate system and the rotation movement amount of each coordinate axis, and the user coordinates newly set by the coordinate conversion means. A control device for an industrial robot, comprising: a system registration number; 3. The G code command according to claim 1 has, as its parameters, a registration number for specifying any one of a plurality of preset coordinate systems and a coordinate system designated by the registration number. A control device for an industrial robot, comprising: a parallel movement amount of a coordinate origin and a rotation movement amount of each coordinate axis. 4. The industrial robot characterized in that the G code command according to claim 1 has, as its parameters, a parallel movement amount of a coordinate origin with respect to a currently set coordinate system and a rotation movement amount of each coordinate axis. Control device.