JPS595072B2 - Automatic welding method using a general-purpose welding robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the creation of a welding method using a general-purpose welding robot, particularly in welding large parts for shipbuilding, by simplifying the programming and control mechanism, and by simplifying the programming and control mechanism. 5. By using automatic welding that can handle a wide variety of parts, we aim to increase the variety of welding processes, increase speed, and improve reliability.

In the Kuku shipbuilding project? It is well known that contact work occupies a large portion of the workforce.

For this reason, there is a strong demand to improve manual or manual automatic welding by a large number of skilled welders, and to improve productivity and reduce costs through labor saving, automation, and speeding up. In response to this, various automatic welding mechanisms have been proposed in the past, but they can be roughly divided into hydraulic systems and electric systems. A typical example of these medium-hydraulic systems is one that uses sensors to accurately position the torch relative to the object. The advantage of this is that the robot can memorize the coordinates, posture, conditions, etc. in detail in advance. The aim is to simplify so-called teaching. Even so, it is unavoidable that there are still many difficulties in dealing with shipbuilding parts that are large and have a wide variety of shapes and sizes. As a representative example of the electrical system, there is also a proposal for a horizontal fillet robot for shipbuilding box-shaped members equipped with sensors. Unfortunately, this is for horizontal use,
The biggest drawback is that vertical welding cannot be performed. Needless to say, it is only used for box-shaped members that are close to right angles, and in addition, separate equipment is required for its installation and movement, making it difficult to handle large-sized members with diverse shapes and dimensions as described above. However, it cannot be said that it is a robot with versatility suitable for diversification, and it should be said that it is still a specialized machine. Including such examples, the following points can be cited as common difficulties with various conventionally known robots.

That is, as described above, even if some models are simplified, there are still difficulties in teaching.

This type of teaching requires a lot of time when the target is a complex and diverse shape or large member, and also leads to complicated programming and control mechanisms. Automatic welding is almost impossible for objects in which one welding unit is long and diverse, from the viewpoint of ensuring accuracy. ◎ Many of the Tsuru robots that have been proposed and put into practical use are semi-fixed types, and their operating range is about 1.5 m at most.
It should be said that it is not suitable for large components for complex shipbuilding.

@As a shipbuilding component, its assembly accuracy, processing accuracy, and delivery positioning accuracy are unreliable.

@ There is still no proposal for a technologically complete robot for arc welding. (e) It is expensive and has poor adaptability.

I can point out various points such as:

To put it simply, we are working on assembly and welding of large parts for shipbuilding, where scallops and snips have stiffeners attached to them, and it is common for these to intersect with each other and obstruct the welding line. It is true that there is still no proposal for a robot that can handle this automatically. This is the current situation, and the establishment of an effective and appropriate mechanism and welding control process has been desired for a long time. The present invention was developed to overcome the current situation, and its features are that it enables the rear robot to freely move back and forth (X-axis) and left and right (Y-axis);
It consists of a mechanism that gives free vertical movement (Z-axis) and its rotational movement (V/axis) to the sensor and main shaft for holding the torch disposed on it, and the above-mentioned movement by the movement of the X, Y and Z control axes The position of the torch is controlled by the servo control system by determining the difference between the current value and command value of each axis as a residual value, adding this residual value and the incremental value output from the computer, and using the obtained value as a command value. However, this allows automatic welding.

Further, other features of the present invention include, in addition to the above configuration, the torch can be moved forward and backward (R axis), the torch can be rotated (θ axis), and the torch itself can be rotated (φ axis), and at least two sensors can be used. By detecting various shapes in the structure of the contacting member, the R-axis, θ-axis, and φ-axis are controlled thereby to finely determine the torch position and orientation, and welding is automatically performed. It is in. This makes it possible to perform automatic and stable welding with simple programming and control mechanisms for roughening shipbuilding parts, which are large, have long welding distances, and are diversified. For example, a single mini-computer can be used as the core of group control for the welding process, from cutting and material distribution to related conveyance systems such as automatic welding. The basic mechanism of the robot used in the present invention is disclosed in Japanese Patent Application No. 51-121674 and Japanese Patent Application No. 51-121675.
An example of its configuration is shown in FIGS. 1 and 2.

That is, the surface plate 11 and the welding robot supports 16a and 16b arranged on the base 1, and the rails 17a and 17b laid on these supports are the support mechanism for the welding robot, and the parts covered on the surface plate are The butt joint materials 12, 13, 14 and 15 are assembled. The basic form of the welding robot is that first, the garters 2a and 2b, the garter monopods 21a and 21d, and 21b and 21c are connected to turn frames 22a and 22b.
between 21a and 21b and between 21c.
A gate-type mechanism is used so that the material to be welded can be placed between -21d and 21d. The turn frame has rail running wheels 29a, 29b, 29c, 29b and guide rollers 23a-23b and 23c-29b in contact with the rail side surface at its lower part.
23d is provided. Furthermore, guide strips 24a and 24b are laid on the gutter, respectively. Movement of such a gate-shaped mechanism is carried out by motors 25a and 25b, pinions 26a and 26b, and a rack 2 fixedly installed along the rail.
This is done by five drives consisting of 7a and 27b.
As shown in this figure, the position detection device 28 of the gate type mechanism
If wheels a and 28b are attached, wheels 29a, 29b,
It is extremely easy to control the position of the portal mechanism through 29c and 29b when the portal mechanism moves and stops (X-axis in the figure). Next, the mechanism for moving the welding robot in the Y-axis direction is as follows.
First, the mobile cart 3 is loaded on the guide strip 24a24b,
This traverse (Y axis) is the motor 31. Pinion 32-rack 33 and wheels, 34a-34a, 34b-34b,
34c-34c, 34d-34d and 35a-35d,
35b to 35c (all of which are provided in contact with the upper, lower, and side surfaces of the guide strip). A detector 36 is disposed on this as shown in the figure, and the wheel 35a is
and 35b to control the movement and stop (Y-axis) of the moving cart. Furthermore, the vertical movement (Z-axis) of the contact point is based on the main shaft 4. This main shaft is held so as to be able to rotate itself (W axis) along with the above-mentioned vertical movement. The basic mechanism is as follows. That is, first, a main shaft holding cylinder 41 is disposed in the center of the movable cart, and a shaft cylinder 42 is inserted vertically into this cylinder via a bearing (not shown), and the main shaft is inserted through this shaft cylinder. Next, the upper and lower parts of this shaft cylinder are provided with rectangular cylindrical vertical movement guides 43a and 43b concentric therewith.
are connected to each other, and at the same time, a gear 44 is fixedly installed in the middle part of the shaft cylinder. Furthermore, one side of the main shaft is provided with a rack 45 for vertical movement.
, on the other side are guide strips 46a and 46 held between guide rollers (not shown) provided on the vertical movement guide.
b is fixedly installed. In such a mechanism, a driving device for vertical movement (Z-axis) of the main shaft is composed of a motor 47 and a gearbox 48, and this gearbox houses a worm mechanism (not shown) and a pinion attached thereto.
The vertical movement of the main shaft is performed by the vertical movement rack and this pinion, and at the same time, by the attached detection mechanism 49,
Its vertical movement and stop (Z-axis) are controlled. On the other hand, the main shaft turning (W axis) device is a gearbox 5 having a motor 50 and a gear mechanism 51-52 therein.
3, and concrete turning is performed by this gear 52 and the aforementioned drive gear 44, but the turning stop (F axis) is controlled by an attached detection mechanism 54. The general-purpose welding robot used in the present invention is capable of accurately controlling the position of the torch with respect to the welding line using the control system for each of the X, Y, Z, and W axes as described above.

However, it goes without saying that the position may need to be further finely adjusted depending on the shape and dimensions of the wide contact member. Such fine adjustments are made by the mechanism described below. In this case, a two-torch system is shown in the accompanying drawings, so the detailed description will be based on this. Now torch 6
a and 6b are torch holding shafts 61a and 61b, respectively
The holding shaft is attached to the main shaft 4 by means of a bracket 62, and this retaining shaft is attached to the bracket by means of attachment means 6.
It is rotatably held within a bearing sleeve (not shown) fixed at 3.

Rotation of the holding shaft (θ axis) is performed by motors 64a and 64b and gear boxes 65a and 65b containing a gear mechanism (not shown) that engages with the holding shaft. In this case, rotation detecting mechanisms 66a and 66b are provided, whereby accurate orientation control of the torch's tangent line by stopping the rotation of the holding shaft (θ axis) can be easily controlled. As mentioned above, once the torch can be correctly oriented toward the tangent line using the W and θ axes, it goes without saying that the distance between the tip of the torch and the tangent line must reach a required level.

Therefore, in the present invention, a mechanism for controlling the advance and retreat of the torch is provided. That is, the connection mechanism between the holding shafts 61a and 61b and the torches 6a and 6b is important, and its basic configuration is as follows. First, horizontal tubes 7a and 7b are fixed to the lower ends of torch holding shafts 61a and 61b. Inside this, the torch drive shafts 71a, 71b and the torch forward/backward shafts 72a, 72b screwed thereto are connected to gear boxes 75a, 75 with a built-in gear mechanism (not shown).
b is arranged. Further, motors 73a, 73b and detection mechanisms 74a, 74 are connected to this gear mechanism.
b is attached. In such a mechanism, by operating the detection mechanism, it is easy to control forward and backward movement and stop (R axis) of the torch via the torch movement axis. Next, the attitude of the torch, that is, the angle adjustment mechanism is as follows. That is, torch holders 76a and 76b are fixed to the torch forward and backward shafts, and therein are torch rotation shafts 77a and 77b, a rotation gear mechanism (not shown), and a torch angle detection mechanism (not shown) that interlocks with the rotation shafts. (e.g. synchronized oscillator, etc.) 78a
and 78b are provided. Furthermore, torches 6a and 6b are fixed to the rotation shaft via torch shafts 79a and 79b. The torch holder has a motor 8.
0a and 80b are attached and connected to the rotation shaft. In such a mechanism, the rotation of the torch (ψ axis) is controlled by the operation of the torch angle detection mechanism. By using the X, Y, Z, V/ control axes mentioned above, and the θ, R, and φ control axes added to these, the position and attitude of the torch can be accurately controlled in response to changes in the rear tangent. If this becomes possible, it will be easy to make welding robots more versatile.

FIG. 3 shows the control shafts extracted from FIGS. 1 and 2. In the present invention, a separate sensor is provided in order to fully utilize the functions of each of the control axes and to correctly control the position and orientation of the welding torch. This basic mechanism is shown in FIGS. 4 and 5. That is, the sensors 100, a-b-c, and e-f-g are attached to one end of the horizontal tubes 7a and 7b via their support shafts 101a and 101b, so that they are on the same plane as the torches 6a and 6b, respectively. configured. In this case, the connection mechanism between the sensor support shaft and the sensor is provided by cylinders 102a, 102b and piston rods 103a, 103b. Such a sensor is connected to the piston rod by its holders 104a and 104b, and inside the holder, as shown in FIG.
Sensor body 1 compatible with 05, 106 and 107
08, 109 and 110 and a detection mechanism 111 are incorporated. The main body of this sensor does not necessarily need to be a specific one; it can be either a conventionally known contact type such as a differential transformer, or a non-contact type such as an eddy current sensor or phototube. be. Such sensors are controlled in position by actuation of the cylinder, depending on their type and performance. The welding robot used in the present invention can detect the shape of the contact member and the weld line thereof every moment using the attached sensor.

According to the information detected by this,
, Z, F, θ, R, and φ control axes, and the position and orientation of the torch are freely controlled and determined. A suitable computer is provided to process such various detected information. Such a control mechanism enables simultaneous control of each control axis, and is not only versatile, but also facilitates numerical control (NC) by using an NC servo mechanism. The basic configuration of the control system for each of the above control axes is shown in Figures 7, 8 and 9, of which the one in Figure 7 is a conceptual program and the one in Figure 8 is a basic program and diagram for each of the control axes. The one in FIG. 9 is a program mainly centered on the interface in each of the above figures.

In the figure, 120 is an electronic computer, 121 is its input/output device, 1
22 is an interface, 123 is an arithmetic control circuit, 12
4 is a digital to analog (11)/A) converter, 12
5 is a jitter-low digital (S//D) or code converter and its amplifier; 126 is a control axis motor controller; 127 is a tacho generator; 128 is a control motor; 129 is a pulse generator or synchro oscillator; 130
are each control axis, 122w is the welder interface, 1
40 is a power source for a welding machine, 141 is a welding machine control device, 142 is a wire supply device for a welding machine, symbol TG is a tachogenerator, PG is a pulse generator, DH is an absolute value type pulse generator, CX is a synchronized oscillator, SD indicates a synchronized digital converter, R indicates the right side, and L indicates the left side. Other numbers are the same as in each of the figures above. The most important thing in controlling the welding robot by the above control system is to accurately position the torch on the horizontal tangent.

For this purpose, it is necessary to position each axis and control the speed at the required welding speed. In the present invention, the premise is that the motor mechanisms for controlling each axis shown in FIGS. 7 and 8 are all based on the NC-servo control system. However, when applying the above control system to a specific welding robot, it has been found that more careful consideration is required. This is because the operating time constants of each control axis are considerably different. This is because the main object of the welding robot according to the present invention is automatic welding of large members for shipbuilding. From this point of view, FIG. 9 shows an example of the interface circuit shown as 122 in the control system shown in FIGS. 7 and 8 above. First, FIG. 9-a shows a control system centered on the interfaces for the R axis and the φ axis among the control axes described above. These R-axis and ψ-axis are the smallest among the control axes of the welding robot, and their working distance and number of rotations are extremely small, so their control system is of the usual absolute type. As mentioned above, this control system is characterized by the synchronized oscillator 129a that is driven by the rotation of the motor, since it precisely controls the position and orientation of the torch relative to the welding line. This output is converted into a digital number by the S/D converter shown as 125a, and is combined with the output of the command value counter 135 from the computer 1 and the arithmetic controller 1.
The output is converted into an analog quantity by a D/A converter 124, and is introduced into the motor control device to control each control axis. Next, the above figure b shows a control system for the F axis and the θ axis.

As mentioned earlier, the W-axis and θ-axis serve as the basis for the R-axis and ψ-axis, but since both are rotating axes, it has been confirmed that the absolute method is sufficient as above. There is. In this case, the only difference from the control system for the R-axis and φ-axis is that the synchronized oscillator is replaced with an absolute pulse generator 129b, and the S/D converter becomes a normal code converter 125b. be.
The control function resulting from this is basically the same as that for the R axis and the φ axis. Furthermore, it has been found that special consideration is required for each of the X, Y, and Z axes.

This is different from the control system for each axis mentioned earlier, as the movement distance for each of the X, Y, and Z axes is large, and this is
This is because if the absolute value method is used, the programming becomes extremely complicated, and the configuration of the control device accompanying this is also not easy. Therefore, the present invention is based on an incremental method, and uses the above-mentioned absolute value method for direct control. The reason why such an increment-one-absolute-value combine method is used is that if only the incremental method is used, for example, when a malfunction such as a miscount occurs in the control device, this will accumulate and cause a large error.
According to the above-mentioned combine method, in addition to the advantages of simplification of Pukagramming and control device in the incremental method,
It is possible to take advantage of the advantages of the absolute value method in that it is easy to convert programs and temporarily stop and resume operation. 1 using such an incremental absolute value combination method
An example is the control system shown in FIG. 9-c. In the same figure, the name of the program other than those mentioned above is 13.
1 is a current value absolute value circuit using a pulse generator 129c;
132 is a remaining value counter for the current value; 133 is an adder; and 134 is an increment counter for the current value. in general,
In a servomechanism, it is normal that a target value and an actual value do not necessarily match. FIG. 10 shows this as one schematic pattern. If a shift such as that shown in the figure were to occur, it would be difficult to automatically reapply at the necessary speed. Needless to say, such a deviation should be compensated for by some means. This is another reason why the increment-one-absolute value combination method was developed in the control system for the X, Y, and Z axes of the present invention. ? In a contact robot, the positioning of the torch with respect to the tangential line and the positioning and speed control of each control axis determine the automatic contact, and for this purpose, it is preferable to adopt an NC servo mechanism for each of the above-mentioned axes. was mentioned earlier. As for positioning using such a servo mechanism, for example, specifically in the case of a single axis, 0.5m7! This is a position control system that issues a position command for each L every 50 msec. The welding speed at this time is 600
It will be mm/Min. Therefore, by changing the above-mentioned 50 msec, the landing speed can be controlled. Under such conditions, in the case of two axes, (0.5C0Sθ) Mll. In the Y direction (0.5S
1nθ) M7! A position command for L will be issued. This is the above-mentioned incremental method, and its basic form is shown in FIG. That is, each position Pl, P2... is (Δ
X1-ΔY1). In the present invention, the current value based on such an incremental method is calculated and stored in the counter shown as 134 in FIG. 9-c. At the same time, the output of the above PGl29c is the remaining value counter 1
32, the difference between the current value and the target value is calculated, and this value is added to the command output of the computer 120 by the absolute value counter 131 at that point in time and the adder 133.
This added value is used as a specific command value by the command value counter 1.
35, the previously calculated increment value is subtracted by the subtracter 123, and an analog quantity is obtained by the D/A converter 124. This is the control amount of the motor 128. In this case, the output of the command value counter 135 simultaneously enters the remaining value counter 132, and the detected current value (PG output of 129c)
The difference between them, that is, the residual value, is calculated. In this way, as described above, the control amount is output in the form of (command+residual value) at regular intervals, and each of the X, Y, and Z control axes is accurately controlled. In other words, the disadvantages of the incremental and absolute value methods as described above are suppressed,
This is a control system that takes advantage of these strengths. The following table schematically shows the functions of such a control system in a normal state. Here, the values described above as an example are adopted for both the distance axis and the time axis. The functions shown in the above table are connected and disconnected at predetermined intervals on both the time and distance axes, and the necessary landing speed can be easily achieved.

As mentioned above, the melting robot according to the present invention is equipped with a sensor.

In concrete automatic welding, sensors are used as the information source for the control system, but when assembling large shipbuilding parts, each sensor corresponding to each surface in the X, Y, and Z directions is configured as one set. This invention is what makes it so special. If a sensor block having such a structure is disposed on the torch shaft, automatic welding can be easily performed on the horizontal and vertical welding lines. In the present invention, if the sensor-based copying mechanism and its process are broadly classified, the following types can be used. That is, 1-sensor leading system, 2-sensor trailing system, 3R-axis control system, etc.

The tracing control by each of these mechanisms will be described in detail below. First of all, it is a sensor advance method.

The sensor advance method is generally well known, but when you examine its substance, it is simply an on/off control system.
Positional deviations occur due to time lag, etc., resulting in poor accuracy. The present invention is an attempt to improve this drawback, and in order to avoid complexity, the functions of a one-torch type will be described and representative thereof. In the case of this one-torch type, the control axes that participate in the control system of the sensor that is actually tracing the wall surface are X, Y, and W.
It is the axis. Now, FIG. 12 shows the above-mentioned sensor-based scanning control mechanism as a program, which has been extracted and organized from the above-mentioned FIGS. 7, 8, and 9.
The important thing here is that the distance between the preceding sensor and the torch is always constant. The second is that the current values (positions) of the sensor and torch are detected at regular intervals (for example, 0.5 ml 50 msec as mentioned above is an example). Such current values, that is, as seen in FIG. Each time, it enters the computer 120, where it is calculated and compared according to a predetermined procedure, and enters the control mechanism 126 as new command values, ΔX, ΔY, and Wl53, where it is controlled as specific analog quantities. This controls the axis. This allows the torch to be accurately positioned relative to the horizontal tangent without reducing the welding speed. Now, suppose the distance between the sensor and the torch is fixed at 5C!!L. , the above detection interval is 1?, 1 sec, and in order to make it easier to understand,
If we take uniaxial copying with only one axis as an example, we can obtain the block shown in Fig. 13 as a copying system of a sensor and a torch. Therefore, in the initial state of copying, the sensor is located at the point 5cTrL in the same figure. Approximately 1.2 seconds later, it passes the point 6α. At this time, the current value of the sensor (
151) in Fig. 12 is read into the computer, and the current value of the torch (also 152) is also input into the computer at the same time, where it is calculated and output as a command value (also 153).
The control shaft 130 is controlled by this command value 153 to determine the position of the torch. In this way, command values are issued while reading data at regular intervals, and welding progresses accordingly. If the copying system shown in FIG. 13 is combined into one algorithm, the flowchart shown in FIG. 14 can be obtained. This is similar to the one in FIG. 13 above, assuming that one round of the loop shown in FIG. 14 takes one second. This value may be appropriately set as a piece of hardware in the computer 120, depending on the required welding speed and other factors.
Now, 155 in the same figure is the current value capture of the torch and sensor, and this output is 151 and 15 in Fig. 12.
Enter the calculator as 2. 156 is a computer output as a command value, and 153 in FIG. 12 is this.

157 shows the calculation of the actual traveling distance in the D below, and the judgment of whether this traveling distance exceeds 1 yen is 158.
And 1C-J MoV! If it is less than, no new sampling points are calculated.

1C! ! If L is exceeded, a new next sample point is calculated and stored in the computer.

This is the step shown as 159. To explain this kind of loop more specifically, in the first second, the torch and sensor are 81]! It will progress to some extent. Since the sample points have a period of 1 second, there is no need to newly calculate and store them here. After 2 seconds, this will change from the initial state to 1
．． It has progressed about 8cm. Here, the coordinate of the wall surface at the point of 1cTrL and 1.8CT! It is calculated by interpolation with the coordinate values in L and stored. This will be used as the command value after 6 seconds. After 3 seconds, the robot has traveled 2.8 cm, so the coordinates at point 2c are determined in the same way.

In this case, the above-mentioned interpolation means that, for example, after 2 seconds,
Considering the sample point in , first, the coordinates as 5 are already known, and this relationship is )5←−−1cTr
It becomes L+6.

After 2 seconds, it is 1.87 from point 5 above! Since the progress is about Jm, the sample point 6 (SX, SY) is
Xs-Sx'1SX=SX'+ Here ~ D- is calculated as (XS-SX)+(YS-SY)2.

On the other hand, the coordinates (XS, YS) of the wall surface determined by the sensor are the 15th
As shown in the figure, if the reference coordinates of the sensor are (P.Q) and the minute displacement of the sensor is 5, then Ir'1n^
1.1r' can be easily calculated.

In this way, the respective coordinates are sequentially detected and calculated by the computer at regular intervals until the end of the welding, and automatic welding can be easily performed by accurately positioning the torch. Next is the sensor trailing method.

Here, contrary to the preceding method, a sensor is fixedly installed behind the torch at a certain distance. FIG. 16 shows the copying process with such a torch-sensor system. In the figure, the algorithm regarding the movement of the torch and sensor connecting each point schematically shown is as follows. First, point 1 in the figure: In this initial state, it is assumed that the position of the torch is deviated by 5 from the reference point.

Point 2: Since the sampling or detection period 4 is determined as described above, @ is obtained from 5 and 4 above, and r is corrected by this @ amount before proceeding.

Point 3: After progressing by @ according to the above steps, calculate the above deviation @ again and proceed.

Point 4: This shows an example where the wall surface is curved. First, the displacement from the virtual wall W at this point @
Check 2.

Point 5: At the same time, F is corrected by (α+β) so that it intersects the virtual wall surface W at the time when the next 4 minutes have passed.

Point 6: Here, repeat the same operation as 1 above again.

According to such an algorithm, it is possible to accurately position the torch without any trouble using the sensor following method, and to perform accurate welding.

In this case, the trailing system control program is the same as that described above in FIG. 12, and the calculation is performed as follows. That is, in Fig. 16 above
1,1' is the computer input 1 from the sensor in Fig. 12.
It is 51.

In this case, the above L is calculated by the following formula. That is, here, X and Y' are the current torch values described in connection with FIG. 12, that is, the data of the computer input 152. The command output 153 calculated by the above-mentioned human power is as follows.

That is,.

With such command values, the torch can be controlled accurately and easily. The above sensor copying system was first installed in Fig. 9b.
It is incorporated into the control system shown in c. and c. and its related description, and serves as its information source.

That is, X, Y and W and/or θ
Each of the control axes of the torch can be accurately controlled, making it possible to easily position the torch. This may be sufficient for normal assembly and connection of parts. However, when assembling large parts for shipbuilding,
As mentioned above, it is well known that they come in a wide variety of shapes and sizes. Therefore, the present invention further incorporates a sensor tracing system for the R-axis and the ψ-axis in order to exhibit fine adjustment and sufficient adaptability to accommodate these various member shapes.
Regarding the shape and dimensions of such members,
First of all, it is known that there are two types of steel plates used as substrates: flat plates and curved plates. Next, there are so-called scallops and snips in the shape of the above-mentioned steel plates as concrete assembly members, and in addition to this, stiffeners etc. are added? In addition to being obstacles to the tangent line, there are also differences in thickness, and a wide variety of combinations of shapes are shown. Needless to say, in the construction of a single ship, there are different combinations of parts depending on the type and purpose of the ship. If these are automatically butt-joined using a sensor copying mechanism, there is a strong possibility that the system using each control axis of X, Y, Z, and W (and θ in the case of a two-torch system) as described above will not be able to cope with the problem. . Since each of the axes of the welding robot for assembling these large components is inevitably large and heavy, the time constant is also large, and the servo mechanism for grasping the current value of each axis, which is adopted in the present invention, is not always necessary. This is because the response is not quick. In the present invention,
This is the reason why R and φ control axes are further provided on the F (or θ) axis for fine adjustment in order to cope with such a shape. FIGS. 17a and 17b show an example of the arrangement of a torch and a sensor configured to detect the end of such a member and its shape. The examples exemplified here are the 4th to 6th ones described in detail earlier.
Although the basic structure is similar to that shown in the drawings and related descriptions, the one shown in FIG. 17 has a mechanical arrangement for achieving tracing control using the R axis including the φ axis. That is, in the figure, A indicates a differential transformer type sensor, and B indicates an eddy current type or LC type magnetic sensor. This is the basic configuration, and in addition to these, C and D sensors, which are also differential transformer types, are added as necessary. Now, looking at the roles that these sensors should play, first of all, magnetic sensor B
This is because the change in the end of the member can be detected as a surface, and this is extremely advantageous in narrow areas.
The reason why the A sensor is of a differential transformer type is that it enables the above-mentioned R-axis to be finely adjusted in an NC manner.
What is most important in the construction and arrangement of the sensors A and B is that they always maintain a constant spacing and height in relation to the torch.
If both sensors are moved at the same time in this relationship, it is possible to detect changes in the end of the member and shape, and to adjust the radius based on this.
Fine adjustment using NC is possible mainly on the axis. In this case, there is no need for special functions for both of the above sensors. An 0N-0FF function that simply knows the starting point and ending point of the shape change in the direction of travel is sufficient. All changes in shape can be covered by changing and combining 0N-0FF of both sensors A as a differential transformer and B as a magnetic sensor. When assembling and welding specific members, it is normal for there to be many obstacles (for example, stiffeners, etc.) in the direction of the welding.

In such a case, it would be difficult to deal with the problem using only the above-mentioned sensors A and B. The sensor for this purpose is shown as C in FIG. 17 above. This is also A
, B sensors, only a simple 0N-0FF function is required, but in short, the 0N of the three sensors A, B, and C above is sufficient.
The present invention is capable of responding to all changes in the shape of members, including obstacles, by changing -0FF and their combinations. Furthermore, if the D sensor shown in Fig. 17 is attached to maintain the height at a constant level, it can be said that it is even more secure. The one shown in FIG. 17 is just one example of its basic configuration, and it goes without saying that other sensors should be provided if necessary. As described in detail above, according to the present invention, it has become literally possible for the first time to create a general-purpose robot that can be used for large-scale robots such as those used in shipbuilding, and whose component configurations are diversified. However, this problem can be effectively dealt with using simple programming and control mechanisms.

The actual benefits from this are truly large, and the efficiency and labor savings of the above-mentioned work can be said to be immeasurable.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the welding robot of the present invention.
The front view of the torch method, Figure 2 is also a side view, and Figure 3 is the front view of the torch method.
The figure is an explanatory diagram of the control system in Figure 1, Figure 4 is a front view showing the arrangement of the sensor, torch, and torch advance/retreat axis in Figure 1, Figure 5 is a side view thereof, and Figure 6 is the same as Figure 4. side, top and rear views showing an example of sensor arrangement according to
Fig. 7 is a block diagram showing the outline of the control system according to the present invention, Fig. 8 is a detailed block diagram thereof, and Fig. 9a is a block diagram showing the outline of the control system according to the present invention.
In the figure, b is a control block diagram using the absolute value method for the R and ψ axes, b is a control block diagram using the absolute value method for the F and θ axes, and c is a combination of the incremental value and absolute value method for the X, Y, and Z axes. 10 and 11 are explanatory diagrams of the incremental value method according to FIG. 9-c, FIG. 12 is a block diagram showing an example of a control system using the sensor preceding method, and FIG. Fig. 14 is a flowchart of this process, Fig. 15
The figure is also an explanatory diagram showing an example of obtaining wall surface coordinates using a sensor, Fig. 16 is an explanatory diagram of the sensor trailing method, and Fig. 17
Figure a is a longitudinal sectional front view of a sensor arrangement for detecting the shape of a connecting member, and figure b is a side view thereof. In the figure, 1 is the base, 11 is the surface plate, 12, 13, 14, and 1
5 is a welding member, 16a and 16b are supports for the clan robot, and 17a and 17b are rails. 2a and 2b are gutter supports, 21a, 21b, 21c and 21d are gutter support legs, 22a and 22b are turn frames, 23a, 23b, 23c and 23d are guide rollers, 24a and 24b are guide strips, 25a and 25b are motors , 26a and 26b are pinions, 27a and 2
7b is a rack, 28a and 28b are position detection devices, 29
a, 29b, 29c and 29d are wheels. 3 is a moving trolley, 31 is a motor, 32 is a pinion, 33
is rack, 34a-34a, 34b-34b, 34c-
34c and 34d-34d are drive devices, 35a and 35
b is a wheel, and 36 is a detector. 4 is a main shaft, 41 is a holding cylinder thereof, 42 is a shaft cylinder, 43a and 43b are vertical movement guides, 44 is a gear, 45 is a vertical movement rack, 46a and 46b are guide strips, 47 is a motor, 4
8 is a gearbox, 149 is a detection mechanism, 50 is a spindle rotation motor, 51 and 52 are gear mechanisms, 53 is a gearbox, and 54a and 54b are detection mechanisms. 6, 6a and 6b are torches, 61a and 61b are torch holding shafts, 62 is a bracket, 63 is a mounting means, 64a and 64b are motors, 65a and 65b are gearboxes, and 66a and 66b are rotation detection mechanisms. 7a and 7b are horizontal cylinders, 71a and 71b are torches and drive shafts, 72a and 72b are torch advance and retreat shafts, 73a and 73
b is a motor, 74a and 74b are detection mechanisms, 75a and 75b are gearboxes, 76a and 76b are torch holders, 77a and 77b are torch rotation shafts, 78a and 78b are torch angle detection mechanisms, 79a and 79b are torch shafts, 80a and 80b is the motor. 100, a-b-c and e-f-g are sensors, 101
a and 101b are its support shafts, 102a and 102b are cylinders, 103a and 103b are piston rods,
104a and 104b are sensor holders, 105,1
06 and 107 are sensitive surfaces for each of the X, Y, and Z axes, 1
08, 109 and 110 are the respective sensor bodies, 1
11 is a detection mechanism. 120 is an electronic computer, 121 is an input/output device, 122 is an interface, 123 is an arithmetic control circuit, and 124 is a D/O device.
A converter, 125 is an S/D or code converter, 126 is a motor controller for control axes, 127 is a tacho generator, 128 is a motor, 129 is a pulse or synchro oscillator, 130 is each control axis, 131 is a current value absolute value circuit,
132 is a residual value counter for the current value, 133 is an adder, 134 is an increment counter, 135 is a command value counter, and 136 is a gear mechanism for each control shaft. 140 is a welder power supply, 141 is a welder control device, 14
2 is the welder wire supply device 150 on the wall, 151 is the detected analog quantity, 152 is the detected digital quantity, 153 is the command value, 155 is the current value taken in, 156 is the output as the command value, 157 is the distance traveled, 158 Judging distance,
159 is a calculator input.

Claims (1)

[Claims] 1. The welding robot can freely move back and forth (X-axis) and left and right (Y-axis), and the sensor and torch holding main shaft provided thereon can freely move up and down (Z-axis) and It consists of a mechanism that gives the rotational movement (Ψ axis), and the position of the torch due to the movement of the X, Y, and Z control axes is determined by calculating the difference between the current value and command value of each axis as a residual value. An automatic welding method using a general-purpose welding robot, characterized in that the value obtained by adding the value and the increment value output from the computer is controlled by a servo control system as a command value, and welding is performed automatically thereby. 2. The welding robot can freely move back and forth (X-axis) and left and right (Y-axis), and the sensors installed on it and the main shaft for holding the torch can freely move vertically (Z-axis) and rotate (Ψ-axis). ), and also allows the torch to move forward and backward (R axis), rotate the torch (θ axis), and tilt the torch itself (φ axis), and
The position of the torch described above due to the movement of each axis is calculated by calculating the difference between the current value of each axis and the command value as a residual value, and adding this residual value to the increment value output from the computer. In addition to controlling with a servo control system, at least two sensors detect various shapes in the configuration of welding parts, and thereby control the R axis, θ axis, and φ axis to finely adjust the torch position and posture. An automatic welding method using a general-purpose welding robot, which is characterized by determining and automatically welding.