JPS5829577A - Controller for welding robot - Google Patents

Abstract

PURPOSE:To deal easily with changes in specifications and to improve the versatility of a controller by converting the specifications of respective apparatus constituting a robot system into parameters. CONSTITUTION:A central processing unit 62 executes process of teaching and playback sequentially in accordance with control programs and teaching data. If in this time the need for the numerical values of parameters for controlling the robot system arises during processing and executing of the control programs, the unit 62 reads the contents of a parameter storing part 68 from the parameter control programs and processes and executes the system control programs after reading the numerical values.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a welding robot, particularly to one used in a welding robot system using a teaching/playback method.

Generally, this type of welding port system includes a control device 10, a teaching box 18,
Robot body 20, welding power source 22, wire feeding device 24
, an external jig 26, a welding torch 28, a welding cable 32, and the like.

The control device 10 includes a display device 12, a keyboard switch 14 for inputting conditions, and a machine operation panel 16. The teaching unit 18 moves each arm (described later) of the robot main body 20 to a desired position using a switch attached thereto, and then stores the position data in the storage unit of the control device 0. let Both the welding power source 22 and the external jig 26 are controlled by the control device 10. However, the wire feeding device 24 is controlled by the welding power source 22. Inquiry jig 2
An object to be welded, that is, a welding work 30 is attached to 6 . Welding torch 28 is attached to the tip of robot body 20. Further, the torch 28 constitutes a 47th arm 58 (described later) of the robot body 20.

FIG. 2 shows the coordinate system of the joint mechanism of the robot body 20. The mechanism consists of the first, second, . whistle 3
．． 4th. Fifth five joints 42°441 46.48.
50 and 1st. Second. 3rd and 4th four arms 52
, 54, 56.58. Each joint 42-5
0 is driven by a motor and decelerated through a speed reducer. The amount of movement of each joint 42-50 is detected and controlled by a position detector directly connected to the motor. In FIG. 2, the position of the tip of the fourth arm 58, which is the torch 28, is
In the Cartesian coordinate system with -Y-Z axes, f(xp y+
Z), and at the same time each arm length 11 to 1
4, and the rotation angle 01 to θ5 of each joint is f (/'1
．． 12.13.14. , θ1,02. θ3. θ4. θ5
) is also represented.

In the multi-joint teaching/playback type robot shown in FIGS. 1 and 2, the robot has two operating modes: a teaching mode and a playback mode (automatic operation). In the teaching mode, first, each arm 52 to 58 is operated by the manual operation switch on the teaching box 18, the tip of the torch 28 is brought to a desired position near the welding work 30, and the posture of the torch 28 is set at a predetermined position. The welding position shall be set as follows. Next, by pressing the record switch on the teaching box 18, the position information (X, Y,
z) and posture information (θ4, θ5) are stored in the teaching data storage section of the control device 10. Move each arm to the point you want to teach in sequence! 1771 while teaching in the same manner. After teaching the position in this way, welding conditions (welding voltage, 1L flow to welding,
1--chi movement sequence yi+: etc.) is taught using the condition input keyboard switch 14, the display device 12, etc. When the teaching is finished, the robot system switches to playback mode, and when the automatic start switch in the machine operation panel 16 is pressed, the robot system automatically moves from the taught point to the taught point in sequence under the taught welding conditions. .

In the teaching/playback robot system configured and operated as described above, the position data of the torch tip is linearly interpolated, and the teaching data is stored in the X, Y, Z orthogonal coordinate system in order to match the human senses. stored in the section. On the other hand, the robot main body 20 has a joint coordinate system with five degrees of freedom, as shown in FIG. 2, and has an arm length! 1 to 14 are treated as fixed lengths C, and the position of the tip of the torch 28 is indicated by the rotation angle (θ1 to θ5) of each joint. Therefore, the kiss? TS)・In order to control the movement of the main body 20,
The control program requires a coordinate conversion formula for converting the joint coordinate system and the straight seat system. Articulated Ron with 5 degrees of freedom”?
In this case, the IJIJ node coordinates are converted to orthogonal coordinates according to the coordinate conversion formula described above.

X= -rmD 1 (l j ainθ2+72at
nθ3-4-13ainθ4)114(8]nθloo
[lθ4蕉θ5+(2)θ1ainθ5)Y==ooo
θ1 (Flainθ2+12thθ3+135mθ4)
-14(oosθlcxMθ4(2)θ5-pictureθ1ai
nθ5) Z=11cmθ2+126DBθ3+13or
rgθ4+14tnθ4(2)θ5 Conventionally, arm length is 1
1 to 14 are considered as constants, and for this reason, it is necessary to improve the machining accuracy and assembly accuracy of the robot body 20 so that the arm length is as close to a predetermined constant as possible. For example, /1=630. 12=
It had to be machined, assembled and adjusted to make it 3oo (am). Further, as for the welding power source 22, different specifications are used depending on the welding purpose. For example, the rated welding current is 15OA.

30OA, 500A, etc. - The blade protection function has a function to detect overcurrent of the welding power source 22, and monitors whether or not there is an overcurrent for each rated value. For example 1
For a welding machine rated at 50A, an overcurrent alarm will be issued if a current greater than 150A flows. Conventionally, overcurrent values were set individually for each specification value.

As mentioned above, in conventional welding robot control devices, constants are used individually for each different specification value (arm length, rated welding current, etc.) of the equipment that makes up the robot system, making the control program complicated. However, it had drawbacks such as the inability to easily change constants. In addition, there was a drawback that machining accuracy, assembly dimensional accuracy, etc. had to be high in order to match the constants.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to create a welding robot that can parameterize the specification values of each device that makes up the robot system and easily deal with changes in specification values. The purpose is to provide a control device.

In order to achieve the above object, the present invention provides a welding port, an IP
In the control device that controls the knot stem, only the portions where the specification values of the system components differ are stored as parameters. The invention is characterized in that it has a control section for controlling.

Hereinafter, preferred embodiments of this invention will be explained based on the drawings.
do. Note that in the following description, descriptions of parts common to the conventional technology will be omitted, and characteristic matters will be mainly described.

What is the welding port according to this invention in Figure 3? 1 shows an example of a control device for the kit. The control device 10 shown in the figure includes a central processing unit (C!PU) 62, a control program 64.1, a teaching data storage section 66, a parameter storage section 68, a common bus line 70,
It has an input/output control section 72, a parameter setting switch 74, a display buffer 76, and a device control section 78. Here, the difference from the conventional one is that the nozzle meter storage section 68
and a parameter setting switch 74, and further includes a parameter control program for storing parameter values keyed into the control program storage unit 64 in the parameter storage unit 68, and reading parameter values from the parameter storage unit 68 as necessary. This is an internal point. The parameter setting switch 74 is set on the condition input keyboard switch 14.

In the control device a configured as described above, the central processing unit 62 sequentially executes teaching/playback processing based on the control program and teaching data. During processing and execution of the control program, when numerical values of parameters for controlling the robot system are required, the central processing unit 62 reads the contents of the parameter storage section 68 according to the make control program. , read the numerical values, and then process and execute the system control program.

Figure 4 schematically shows how the seven meters are actually stored. Nine meters P1 is the upper limit of the welding voltage, and P2 is the two currents of the peak current and base current. Peak welding current upper limit value for the type of welding machine with P
3 is the upper limit value of the base welding current, P4 is the upper limit value of the wire feeding speed, P5 to P8 are the arm lengths of the gat main body, and P9 is the type of welding machine.

For example, when processing the coordinate transformation program stored in the control program storage section 64, the values of arm lengths 71 to 14 are required, so the central processing unit 62 reads parameters P5 to P8 into the parameter storage section 68. Go to increase, 11 = 630° 12 = 800. 13=140.
14=300 is read, and the calculation of coordinate transformation is 63 each.
Use the numerical values 0s800y140.300. Also,
If the actual arm length is 11-620, input P5=620 into the parameter storage section.In the subsequent processing, the value 620 is used for 11, and the coordinates (x, y, z ), the type of welding machine connected is 5.
If the rating is 0OA, by inputting P2=500 into the parameter storage section 68, an overcurrent warning will be issued only when IP exceeds 500A.

FIG. 5 shows a parameter display screen. This screen is displayed when the key presses the ie parameter setting switch 74 in the negative switch 14. To set parameters using this screen, first enter the key PIN number in the parentheses following the letters "KEY" to prevent erroneous operation, and then enter the parameter value by pressing the key in the one-hand switch 14. Key in using the numeric key switch,
By pressing the input switch? parameter storage section 6B
to be memorized. The parameter storage unit 68 includes, for example, a memory with battery backup (so-called RAM),
Using arbitrary writable memory such as core memory, wire memory, bubble memory, etc., the robot's user can set its parameters. If it is possible for the user to set the diameter, it will be possible for the user to change the torch and welding power source, and even if the torch collides with a jig or the like and the dimensions change slightly,
If you actually measure the dimensions after the change and re-enter the parameters,
-1: It has the advantage of being usable.

In the above embodiment, the robot user can change the parameters arbitrarily, but a read-only memory (so-called ROM) may be used in the noclameter storage unit 48 to prevent the customer from changing the parameters arbitrarily. . In this way, it is possible to prevent the user from changing the parameters by mistake.

As described above, according to the present invention, the specification values of each device constituting the Hpt system are used as parameters, and the control device can be made more versatile, and the mechanical processing of the rodet main body can be made more flexible. The advantage is that even if the accuracy is somewhat poor or the torch etc. is bent, the positioning can be done with high precision, and the component equipment can be easily positioned.

[Brief explanation of drawings]

Figure 1 shows an example of the system configuration of a teaching/playback type arc welding Ronpit, and Figure 2 shows an example of the system configuration of a teaching/playback type arc welding Ronpit. FIG. 3 is a block diagram showing an example of the control device a according to the present invention;
FIG. 4 is a schematic diagram of the parameter storage section, and FIG. 5 is a diagram showing an example of a parameter display screen. Identical members in each figure are given the same reference numerals, and IO is a control device;
12 is a display device, 14 is a key yl"-de switch for inputting conditions, 16 is a rear tl)A operation device, and 18 is a teaching +
l-tux, 20 is the mouthpiece body, 22 is the welding power source, 2
4 is a wire feeding device, 26 is an external jig, and 28 is a welding device 1.
-H, 30 welding workpieces, 32 is cable, 42, 44
, 46, 48, 50 are the first, second . Third. 4th. The fifth joint, 52.54°56.58, is the first joint. Second. Third. Fourth
arm, 62 is a central processing unit, 64 is a control program storage section, 66 is a teaching data storage section, 68 is a parameter storage section, 70d is a common bus, 72 is an input/output control section, 74 is an ie
parameter setting switch, 76 is a display data buffer, 7
8 is a device control section. Agent Patent attorney Shin Kuzuno - (1 other person)

Claims (1)

[Claims] (1) In a control device that controls a welding loop pit system, there is a parameter storage section that stores only the parts where the specification values of system components differ as parameters, and a constant stored in the parameter storage section is used to control the welding port. 1. A control device for a welding spout, comprising: a control section for controlling a weld cut system.