JPH0683416A - Controller for robot with small graphic machining unit - Google Patents

Abstract

PURPOSE:To improve the handleability of a small graphic machining unit by performing continuous operation by combining a track drawn by the small graphic machining unit with a track drawn by a robot arm. CONSTITUTION:The robot for small hole machining has multiple multi-axial joints, and also has a wrist 1b at its tip arm 1a and a small-hole cutting machining unit 2 in two-gravity-center eccentric structure where a torch 3 for cutting is clamped, is fitted to the wrist 1b. The respective shafts of the robot 1 and the driving shaft of the torch 3 are so controlled that the tip of the torch 3 moves along a path up to the start point of a small graphic form and the reference position of the machining unit 2 is set at the center position of the axis of rotation of the small graphic form. The driving shaft is controlled so that the tip of the torch 3 draws the small graphic form from the starting point to the end point of the small graphic form. Then the respective shafts of the robot 1 and the driving shaft of the torch 3 are so controlled that the tip of the torch 3 moves along a path after the end point of the small graphic form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot having a small figure processing unit for gripping a tool such as a plasma torch or a laser torch and cutting a small figure such as a small circle. In particular, the present invention relates to a control device for a robot having a small figure processing unit that synchronizes the movement of each axis of the robot and the movement of a tool driving axis of the small figure processing unit to perform continuous work.

[0002]

2. Description of the Related Art Conventionally, in a small hole cutting robot that performs processing such as small hole cutting, a small hole cutting unit is attached to the tip of a robot arm having multiple degrees of freedom, and a plasma plate is attached to this small hole cutting unit. -Hold a cutting tool such as a chisel or a laser torch, and drive the tool with a drive mechanism provided in the small hole cutting unit to draw a desired trajectory on the tool. I try to cut it.

An invention of this kind is disclosed in JP-A-63-23.
There is a publication of 5073. According to the present invention, a small hole cutting unit having a double eccentric structure, which is driven independently of the movement of each axis of the robot arm, is provided at the tip of the robot arm having multiple degrees of freedom. Then, by driving each axis of the robot, the reference position of the processing unit is positioned at a predetermined position on the work to be processed. For example, when cutting a small circle, the tip of the tool gripped by the small hole cutting unit based on the radius data of the circle to be processed without moving each axis of the robot is the small hole cutting process. The tool drive shaft of the unit rotates about the above-mentioned reference position as the center of rotation, and the small circle is cut.

[0004]

In the above invention, the tip of the tool can be moved by the tool driving shaft of the small hole cutting unit having a low inertia independently of the movement of each axis of the robot. Although there is an advantage that small holes such as circles can be cut with high accuracy and speed, the processing range of the present invention is a circle, a square, or a circle within a two-dimensional plane range limited by the movement of the tool driving shaft of the small hole cutting unit. There is a problem in that it is limited to drawing oval shapes and the usage of the small hole cutting processing unit is also limited to the above. The present invention has been made in view of these circumstances, and it is possible to perform continuous work by combining a locus drawn by a small figure machining unit such as a small hole cutting machining unit and a locus drawn by a robot arm. An object of the present invention is to provide a control device for a robot that improves the usability of a graphic processing unit.

[0005]

In order to achieve the above object, according to the present invention, a small figure processing unit having a tool is attached to the tip of an arm of a robot, and each axis of the robot is controlled by driving. The reference position of the small figure processing unit is moved along a predetermined path on the workpiece, and the tool drive shaft of the small figure processing unit is driven and controlled to rotate the tip of the tool about the reference position as a rotation center to a predetermined value. In a controller of a robot having a small figure processing unit adapted to draw a small figure of a shape on a work, when moving the tool tip along a path having a part of the small figure in the middle, In the path up to the starting point of the small figure, the tool tip moves along the path and the tool tip moves to the small point. When the robot is positioned at the starting point of the shape, the robot axes and the tool driving axes are controlled so that the reference position of the small figure processing unit is located at the rotation center position of the small figure, and the starting point of the small figure is set. In the path from the end point to the end point, the tool drive shaft is drive-controlled so that the tool tip draws the small figure, and in the path after the end point of the small figure, the tool tip is moved along the path. Each axis of the robot and the tool drive axis are drive-controlled so as to move.

[0006]

According to the structure of the present invention, when the tip of the tool is moved along a path having a part of a small figure in the middle,
In the path up to the start point of the small figure, the reference position of the small figure processing unit is set so that the tool tip moves along the path and when the tool tip is located at the start point of the small figure. Each robot axis and tool drive axis are drive-controlled so as to be positioned at the center of rotation. In the path from the start point to the end point of the small figure, the tool drive axis is drive-controlled so that the tool tip draws the small figure. Then, in the path after the end point of the small figure, each robot axis and the tool drive axis are drive-controlled so that the tool tip moves along the path.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 conceptually shows the structure of the small hole machining robot of the embodiment. The small hole machining robot 1 has a multi-axis and multi-joint structure (here, it has a six-axis structure), and a wrist 1b is provided on a tip arm 1a of the robot 1, and the wrist 1b is provided. A small hole cutting unit 2 having a double eccentric structure, which holds a cutting torch 3, is attached to the. Each axis of the robot 1 (hereinafter,
The robot axis is driven by the motors M1 to M6 shown in FIG. 3, and the compass rotation axis 13 and the compass radius axis 11 (hereinafter, referred to as the "compass rotation axis" 13 of the small hole cutting processing unit 2 shown in FIG. 2).
Collectively referred to as compass axis) is a motor V and a motor W
Driven by.

FIG. 2 is a schematic diagram of a drive system of the small hole cutting processing unit 2. A gear Z3 is fixed to the compass rotating shaft 13 of the motor V, and a gear Z4 meshes with the gear Z3. The gear Z4 is supported so as to rotate around the center position C of the compass, and the gear Z2 is supported inside the gear Z4 via a bearing 14. On the other hand, a gear Z5 is fixed to the compass radius shaft 11 of the motor W, and a gear Z6 meshes with this gear Z5. A drive shaft 12 is fixed to the gear Z6, a gear Z1 is fixed to the opposite side of the drive shaft 12, and a gear Z2 is meshed with the gear Z1. The gear Z1 rotates about the compass center position C, while the gear Z2 rotates about an axis Cg that is eccentric by d1 from the compass center position C. A torch 3 is attached to the gear Z2 at a distance d2 from the axis Cg.

Assuming that the distance between the center position C of the compass and the tip position P of the torch 3 is r, the motor W is driven to drive the gear Z5, the gear Z6, the gear Z1 and the gear Z2. And rotate, which changes the distance r.
When the motor V is driven in the state of the predetermined radius r, the gear Z4 rotates around the center position C of the compass, and the torch 3 further rotates.

However, since the gear Z2 is rotatably supported by the gear Z4 via the bearing 14, when drawing a circle having a radius r, the radius r does not change when the gear Z4 rotates. -Turn-around correction for synchronously rotating the counter W in the reverse direction is performed.

Any shape other than a circle (square, oval,
When drawing a (circle angle), the synchronous speed between the motor V and the motor W is appropriately changed, and the motor V is rotated in accordance with the rotation.
By changing the radius r determined by the rotation of the tab W, an arbitrary shape (square, ellipse, circle) can be drawn.

FIG. 3 shows a control configuration diagram of the robot axis and the compass axis of this embodiment. The arithmetic and control unit 4 has compass axes connected via servo amplifiers AMPv, AMPW, AMP1 to AMP6. Drive motor V
, W and robot axis drive motors M1 to M6 to output control signals to control the drive of each motor, and to calculate the cutting locus according to the cutting pattern data input. Therefore, the calculation is performed, and thereby the cutting locus control of the small hole machining robot is performed. In addition,
This cutting pattern data is composed of the following parameters.

[0014] Hereinafter, the cutting trajectory control of the arithmetic and control unit 4 will be described.

The arithmetic and control unit 4 calculates the difference between the tip end position P of the torch 3 and the compass center position C as the coordinate position (x, y).
Then, by compensating the compass center position C, drive control is performed in synchronization with the interpolation operation of the robot axis and the compass axis operation. The basic idea of the interpolation method and the interpolation operation will be described with reference to FIGS.

First, a method of interpolating the center position of the tip of the robot arm in the teaching process to the arithmetic and control unit 4 will be described with reference to FIG. In the teaching to the arithmetic and control unit 4, two kinds of compass languages for controlling the compass axis are provided, one for a single drawing and the other for overlapping the front and rear steps. Further, the work area of the arithmetic and control unit 4 is provided with a compass operation target value table for storing the operation target value position of each axis, and the cutting locus generated by the input of the above-mentioned parameters is stored in this table. -Remember Bull.

The teaching process for the arithmetic and control unit 4 in the case of steps l, m and n will be described below.

The teaching process of steps l, m and n is performed by the arithmetic and control unit 4 before steps l-1, m-1 and n-1 and after steps l, m and n. After continuously teaching steps l + 1, m + 1, and n + 1, the teachings of steps l, m, and n are performed. At this time, the teaching process of steps l-1, m-1, n-1 and steps l + 1, m + 1, n + 1 is performed with the tip position P of the torch 3 fixed to the compass center position C. .

Then, steps l, m and n are additionally taught to the arithmetic and control unit 4 in the language for overlapping,
After that, steps l-1, m-1, n-1 and step l +
The following synthesizing process is performed by 1, m + 1, n + 1 and steps 1, m, n.

4 (a), 4 (b) and 4 (c) show different cases.

Here, steps l-1, m-1, n-1
And a step 1 + 1, m + 1, n + 1, the boundary coordinate is a, the center coordinates of the steps 1, m, n are O, the distance between the boundary coordinate a and the center coordinate O is x, and the length of the long side of the figure is Let y be the value of half the height or the value of the radius.

FIG. 4A shows the case when x ≧ y. In this case, the locus is drawn by the solid line portion in the figure. That is, in step l-1 and step l + 1, interpolation movement including the robot axis and the compass axis is performed,
In step l, the robot axis is stopped and only the compass axis is moved.

FIG. 4B shows the case when x = 0. In this case, the locus is drawn by the solid line portion in the figure. That is, in steps m-1 and m + 1, interpolation movement including the robot axis and the compass axis is performed, and in step m, the robot axis is stopped and only the compass axis is moved.

FIG. 4C shows a case in the case of x <y. In this case, the locus is drawn by the solid line portion in the figure. That is, in steps n-1 and n + 1, the interpolation movement including the robot axis and the compass axis is performed, and in step n, the robot axis is stopped and only the compass axis is moved.

It is to be noted that the use of the cases shown in FIGS. 4 (a), 4 (b) and 4 (c) and the determination of the execution locus are performed when the steps l, m and n are input to the arithmetic and control unit 4.

Next, the interpolation operation of the robot axis and the compass axis by the arithmetic and control unit 4 will be described with reference to FIG.
This will be described with reference to (b) and (c). In addition, FIG.
4B and 4C show interpolation operations corresponding to FIGS. 4A, 4B, and 4C, respectively.

In FIG. 5A, the starting coordinate D of step l-1 and the final coordinate E of step l + 1 and step l
Assuming that the center coordinate is 0, the movement of the tip position P of the torch 3 from the start coordinate D of step 1-1 to the locus start coordinate A of step l is performed by linear movement by the robot axis. Further, the movement of the compass center position C from the start coordinate D of step l-1 to the center coordinate O of step l is performed by linear interpolation by the robot axis. That is,
The compass center position C is finally the center coordinate O of step l.
Will be located in. Then, the movement of the tip end position P of the torch 3 from the center position C of the compass to the locus start coordinate A in step 1 is performed by linear movement on the compass axis. These movements are carried out in synchronization, and from the start coordinate D of step l-1 of the compass center position C to step l
To the center coordinate O of the torch 3 and from the compass center position C of the tip position P of the torch 3 to the locus start coordinate A of step 1 move the tip position P of the torch 3 in the y-axis direction. It is controlled so that it does not combine and moves.

In FIG. 5B, the starting coordinate D at step m-1, the final coordinate E at step m + 1, and step m.
Assuming that the center coordinate is 0, the movement of the torch 3 tip position P from the start coordinate D in step m-1 to the locus start coordinate A in step m is performed by linear movement by the robot axis, and again in step m. The movement of the compass center position C from the start coordinate D of -1 to the center coordinate O of step m is performed by linear interpolation by the robot axis, and the compass center position C
Will eventually be located at the center coordinate O of step m. Then, the movement of the tip end position P of the torch 3 from the center position C of the compass to the locus start coordinate A of step m is performed by linear movement along the compass axis. These movements are performed in synchronization, and the movement of the compass center position C from the start coordinate D of step m-1 to the center coordinate O of step m and the step of moving the compass center position C from the compass center position C of the tip position P of the torch 3 are performed. The movement of m to the locus start coordinate A is controlled so as to move the tip end position P of the torch 3 so as not to move in the x-axis direction.

That is, the movement of linear interpolation by the robot axis between the start coordinate D of step m-1 and the center coordinate O of step m and the tip end position P of the torch 3 by the compass axis.
Starting point A of the trajectory of step m from the center position C of the compass
The movement of the linear movement to is made the same and it cancels.

In FIG. 5C, assuming that the start coordinate D of step n−1, the final coordinate E of step n + 1 and the center coordinate O of step n, first, the start coordinate D of step n−1 to the step n of step n are obtained. The movement of the tip end position P of the torch 3 toward the locus start coordinate A is performed by linear movement by the robot axis, and the compass center position C from the start coordinate D of step n-1 to the center coordinate O of step n. Movement is performed by linear interpolation using the robot axis, and the compass center position C
Will eventually be located at the center coordinate O of step m. Then, the movement of the tip end position P of the torch 3 from the center position C of the compass toward the locus start coordinates A in step n is performed by linear movement along the compass axis. These movements are performed in synchronization with each other, and the tip position P of the torch 3 at this time is moved.
Are controlled so as to move in a combined manner so as not to move in the x-axis direction and the y-axis direction. That is, step n-1
From the center position C of the compass at the tip position P of the torch 3 by the robot axis between the start coordinate D of step No. 3 and the center coordinate O of step n to the trajectory start coordinate A of step n by the compass axis. The movements of the linear movement are made the same to cancel each other.

The operation procedure of the arithmetic and control unit 4 of this embodiment based on the above interpolation method is shown in the flow charts of FIGS. 6 and 7.
An explanation will be given with reference to the chart.

In the teaching process for the arithmetic and control unit 4 shown in FIG. 6, first, the teaching is performed by successively performing steps l-1, m-1, n-1 and steps l + 1, m + 1, n + 1. . At this time, the robot axis is set so that the center position C of the compass is at a predetermined position by the robot axis. That is, the center position of the tip of the robot arm, the center position C of the compass, and the tip position P of the torch 3 are set to coincide with each other (step 101).

Then, the teaching of steps l, m and n is performed. Here, numerical values of parameters (for example, v, L, etc.) corresponding to the cutting pattern data of steps l, m, and n are input (step 102), and the arithmetic and control unit 4 receives the numerical values. The target coordinates of the tip position P of the torch 3 are calculated (drawing locus is generated), and the calculation result is stored in the compass operation target value table provided in the calculation control device 4 (step 103).

Next, the arithmetic and control unit 4 carries out step l,
A calculation is performed to obtain intersection coordinates a and contact coordinates A and B between m and n and the preceding steps l-1, m-1, n-1 and the subsequent steps l + 1, m + 1, n + 1 (step 104).
As a result of this calculation, the intersection coordinates of steps l-1, m-1, n-1 and steps l + 1, m + 1, n + 1 are defined as a, and the final target coordinates of steps l-1, m-1, n-1 are defined as A. , And the start coordinates of steps l + 1, m + 1, and n + 1 are set to B (step 105). The arithmetic and control unit 4 stores the final target coordinates A and the start coordinates B in the compass operation target value table (step 106) and ends the teaching process.

Next, the operation of the arithmetic and control unit 4 which has been taught will be described with reference to FIGS. 5 and 7.

First, the arithmetic and control unit 4 stores steps l-1, m-1, stored in the compass operation target value table.
From the starting point D, the steps n-1, m-1,
A drive signal is output to the motors V and W that drive the compass shafts and the motors M1 to M6 that drive the robot shafts so as to start execution toward the final target coordinate A of n-1 (step 201). ). Then, the motors M1 to M6 are driven, and the robot axis is driven by the motors M1 to M6, whereby the tip position P of the torch 3 is set to the final target of steps l-1, m-1, n-1. It is linearly moved toward the coordinate A (step 202). At the same time, the center position C of the compass is moved to step l by this robot axis.
Linear interpolation is performed on the center coordinates O of the teaching of m and n (step 203). At the same time, the motor V and the motor
The motor W is driven and the compass axis is the motor V and the motor W.
Driven by. As a result, the tip position P of the torch 3
From the compass center position C to steps l-1, m-1, n
It is linearly moved toward the final target coordinate A of -1 (step 204).

The operations from step 202 to step 204 are executed in parallel, and the compass center position C is calculated from the start coordinate D of steps l-1, m-1, n-1 to the tee of steps l, m, n. -Move to the center coordinate O that has been drawn, and the tip position P of the torch 3 is moved to step l-1, m-
The cutting locus is drawn by linearly moving from the 1, n-1 start coordinate D to the final target coordinate A.

Next, the arithmetic and control unit 4 starts each of the motors V, W, M1 to M6 so as to start the operation of steps l, m and n stored in the compass operation target value table.
The drive and stop signals are output to (step 205).
Then, the motors M1 to M6 for driving the robot axis are stopped, and thereby the robot axis is stopped, and the center position C of the compass is fixed to the center coordinate O taught in steps l, m, and n. On the other hand, the motors V and W are driven, and the compass shaft is driven by the motors V and W. Then, the tip position P of the torch 3 is changed to the step l.
From the final target coordinates A of -1, m-1, n-1 to step l
A cutting locus based on the cutting loci of steps l, m, and n stored in the compass operation target value table up to the start coordinate B of +1, m + 1, n + 1 is drawn (step 20).
6).

Further, the arithmetic and control unit 4 stores the next step l + 1, m stored in the compass operation target value table.
A drive signal is output to each of the motors V, W, M1 to M6 to start execution of the +1 and n + 1 operations from the start coordinate B toward the final target coordinate E (step 207). Then, the motors M1 to M6 are driven, and the robot axes move.
The tip position P of the torch 3 is driven by the motors M1 to M6 and the final target coordinates E of steps l + 1, m + 1, n + 1.
Is linearly moved toward (step 208), and further the compass center position C is moved to step l + by the robot axis.
Linear interpolation is performed on the start coordinates B of 1, m + 1, n + 1 (step 209). At the same time, the motor V and the motor W are driven, the compass shaft is driven by the motor V and the motor W, and the tip position P of the torch 3 is linearly moved toward the compass center position C. (Step 210).

The operations from step 208 to step 210 are executed in parallel, and the compass center position C is determined from the taught center coordinates O of steps l, m and n to the final target of steps l + 1, m + 1 and n + 1. Move to the coordinate E and move the tip position P of the torch 3 to the step l +
The cutting locus is drawn by linearly moving from 1, m + 1, n + 1 start coordinates B to final target coordinates E. In this way
The loci of steps l-1, m-1, n-1 where the reference position changes and steps l, m, n and steps l + 1, m + 1, n + 1 can be continuously drawn by the torch 3.

The embodiment has been described on the assumption that it is applied to a robot for cutting work, but the invention is not limited to this and can be applied to a robot for performing arbitrary work such as sealing work.

[0042]

As described above, according to the present invention, the locus drawn by the small figure machining unit such as the small hole cutting machining unit and the locus drawn by the robot arm are combined to perform continuous work. Therefore, the usability of the small figure processing unit is dramatically improved, and the workability of the robot is dramatically improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a robot having a small figure processing unit according to the present invention.

FIG. 2 is a schematic diagram showing a configuration of a drive system of the small hole cutting processing unit of the embodiment.

FIG. 3 is a block diagram showing a configuration of an apparatus for controlling a robot axis and a compass axis in the robot of the embodiment.

FIG. 4 is a diagram for explaining a teaching process in the embodiment.

FIG. 5 is a diagram used for explaining an interpolation operation of a robot axis and a compass axis of the robot of the embodiment.

FIG. 6 is a flow chart showing a teaching processing procedure of the arithmetic and control unit of the embodiment.

FIG. 7 is a flowchart showing a control procedure of a robot axis and a compass axis by the arithmetic and control unit of the embodiment.

[Explanation of symbols]

 1 Robot arm 2 Small hole cutting processing unit 3 Torch 4 Arithmetic controller C Compass center position P Torch tip position

Claims (1)

[Claims] 1. A small figure processing unit having a tool is attached to the tip of an arm of a robot, and by driving and controlling each axis of the robot, the reference position of the small figure processing unit is moved along a predetermined path on a workpiece. And a small figure of which the tip of the tool is rotated about the reference position as a center of rotation by driving and controlling the tool drive shaft of the small figure processing unit to draw a small figure of a predetermined shape on the work. In a controller of a robot having a processing unit, when moving the tool tip along a path having a part of the small figure in the middle, in the path to the starting point of the small figure, the path So as to move the tool tip along the base of the small figure processing unit when the tool tip is located at the starting point of the small figure. Each of the robot axes and the tool drive axis are drive-controlled so that the position is located at the rotation center position of the small figure, and in the path from the start point to the end point of the small figure, the tool tip is Drive control of the tool drive axis is performed so as to draw a figure, and in a path after the end point of the small figure, drive control of each robot axis and the tool drive axis is performed so that the tool tip moves along the path. A control device for a robot having a small figure processing unit.