JPH0635060B2 - Position control device for welding robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to welding of a horizontal base material and a vertical base material forming a peripheral surface, such as a grid-shaped large steel structure such as a ship hull block. The present invention relates to a welding robot position control device for controlling the position of a welding robot applied to welding a welded portion.

[Conventional technology]

Generally, the operating range of a robot is determined by the length of the arm, so the robot with the optimum arm length is selected according to the size and type of the target work, or a peripheral device such as a gate type placer, manipulator or positioner. It is common practice to use a device type robot in which the above are combined.

However, as in the former case, in order to select a robot having an arm length corresponding to a target work, it is very uneconomical to prepare a robot for each target work.

On the other hand, when using the latter device type robot, there is a constraint that the equipment is very expensive and the applicable stage of the robot is fixed, and at present, the device type robot is applied only to a limited work. Absent.

That is, as shown in FIG. 13, a skin (S) as a horizontal base material and a long body as a vertical base material forming the peripheral surface.
(L) and transformer (T) When welding the welded portion of a large structure such as a hull block, the running cost of the device type robot described above is too high. , Or semi-automated means, while moving from joint to joint, distributed application is performed.

[Problems to be solved by the invention]

However, when performing welding with such a portable robot, it is necessary to weld the welded part within the operating range with the robot fixed at the origin position, so if the welded part is concentrated within the operating range. However, there is a problem in that the number of times that the portable robot is handled is large in order to weld the large-sized structure described above, and the arc time rate is reduced.

Therefore, in the present invention, the position of the welding robot is automatically controlled by the detection signal from the distance sensor, and the welding of the horizontal base metal and the vertical base metal forming the peripheral surface is performed like the hull block. A technical issue is to enable automatic and efficient welding.

[Means for solving problems]

Then, means for solving the above-mentioned problems of the prior art will be described with reference to FIGS. 1 to 4 corresponding to the embodiment.

That is, in the position control device of the welding robot (1) for controlling the position of the welding robot (1) for welding the welded portion of the horizontal base material and the vertical base material forming the peripheral surface, in the present invention, the welding robot A base (2) equipped with (1), and a plurality of wheels (4a) rotatably provided on the base (2),
(4b) and a plurality of non-contact distance sensors (8 provided on the base (2) for detecting the distance between each of the vertical base materials and outputting a detection signal.
a) to (8e), and at the time of welding the corner portion of the welded portion, the work origin less than the maximum working distance of the manipulator (1b) of the robot (1) and the operation center of the manipulator (1b) by the detection signals. The wheels (4a), (4b) that derive the deviation from the point M and make the deviation zero
A movement control panel (10) as a deriving means for deriving the moving direction and the amount of rotation of the motor, and the motor (6a) as a driving means for driving the rotation amount in the derived moving direction of the wheels (4a), (4b). ), (6b) are provided, and at the time of welding the straight portion of the welded portion, the wheels (4a), (so that the distance from the vertical base metal to the operation center point M becomes constant by the respective detection signals. A technical means is added to the movement control board (10) to add a function as a copying control means for controlling 4b).

[Action]

Therefore, according to the present invention, the detection signal from each sensor (8a) ~ (8e), the work origin of the maximum operating distance of the manipulator (1b) of the welding robot (1) is set, and the work origin and The movement control panel (10) controls the wheels (4) so that the deviation from the operation center point M of the manipulator (1b) becomes zero.
a) and (4b) are driven, the position of the welding robot (1), that is, the operation center point M as the robot reference point is controlled to a predetermined position, and the operation center point during welding of the corner of the welded portion. M is arranged so as to coincide with the work origin, and at the time of welding the straight part of the welded part, the base (2) runs while the operation center point M is kept at a constant distance from the vertical base metal, and the horizontal base Welding of the material and the vertical base metal is performed.

〔Example〕

Next, the present invention will be described in detail with reference to FIGS. 1 to 12 showing one embodiment thereof.

1 to 3, (1) is a welding robot, and the robot body (1a), the manipulator (1b) consisting of a plurality of arms attached to the body (1a), and the tip arm The attached welding torch (1c) and the torch (1c)
The robot body (1a) is directly fixed to the rectangular base (2), and the wire feeder (1d) is a supporting member. It is fixed to the base (2) by (3), and the welding robot (1) is mounted on the base (2).

(4a) and (4b) are wheels rotatably provided at the left end of the base (2), and steering motors (5a) and (5b) mounted on the base (2) as drive means. The movement directions of the horizontal base metal are controlled by the horizontal servomotors, and the rotation amounts are controlled by the traveling servomotors (6a), (6b) mounted on the base (2) as driving means. Wheels (4a), (4
b) rolls.

Wheels (7a) and (7b) are rotatably mounted on the right end of the base (2).
(4a) and (4b) are rollers that perform the same movements, (8a) to (8e) are non-contact type first to fifth distance sensors (hereinafter referred to as “first to fifth distance sensors”, which are ultrasonic sensors provided on the base (2). First to fifth sensors), the first to fourth sensors (8a) to (8d) are arranged at the four corners of the base (2), and the fifth sensor (8e) is the base (2). Is located in the center of the right end of the, and the distance from the front vertical member by the first and third sensors (8a) and (8c) is the vertical distance from the rear vertical member by the second and fourth sensors (8b) and (8d). The distance to the member and the distance to the right vertical member are detected by the fifth sensor (8e), and a detection signal is output.

(9) is a limit switch provided at the center of the left end of the base (2), and (10) and (11) are a movement control panel and an A / D conversion unit attached to the support member (3), respectively.

Next, FIG. 4 showing the block configuration of the control circuit will be described.

In FIG. 4, (12) is a welding robot control panel provided in the welding robot (1), which controls the manipulator (1b) and also the welder interface unit (13).
The welding output is controlled via.

(14) is an interface circuit into which the detection signals from the sensors (8a) to (8e) converted into digital signals by the A / D conversion unit (11) are input, and (15) is a numeric keypad, a ready key, etc. A keyboard consisting of the operation keys, (16) is a panel interface circuit, (17) is a RAM, and (18) is a signal to and from the welding robot control panel (12) via the I / O interface circuit (19). CPU for inputting / outputting data, and (20) is a digital servo circuit for controlling data from CPU (18) and pulses for each servo motor (5a), (5b), (6a), (6b) Based on the signals from the generators (21a) to (21d),
Servo control of each servo motor (5a), (5b), (6a), (6b) is performed, and CPU (18), each interface circuit (14), (16), (19), Keyboard (15), RAM (1
The movement control board (10) is composed of 7) and the servo circuit (20).

At this time, the movement control panel (10) having the above-mentioned configuration, when welding the corner portion of the welded portion, detects the work origin of the manipulator (1b) or less by the detection signals from the sensors (8a) to (8e). And a manipulator (1b) with a function as a derivation means for deriving a deviation from the operation center point of the manipulator, and deriving a moving direction and a rotation amount of the wheels (4a), (4b) for making the deviation zero, When welding the straight part of the wheel, the wheels (4a), (4b) are fixed so that the distance from the vertical base metal to the operation center of the manipulator (1b) is constant by the detection signals from the sensors (8a) to (8e). ) Is controlled as a copying control means.

Next, the operation of the above embodiment will be described.

Now, as shown in the flow chart of Fig. 5, the welding robot (1) is installed together with the base (2) on the horizontal base material, and the keyboard is installed.
When the ready key of (15) is turned on, C on the movement control panel (10)
The PU (18) determines whether or not a movement command has been input. If there is an input, that is, if YES, the left origin adjustment or right origin adjustment processing is performed, and then the positioning completion signal is used for welding robot control. It is output to the panel (12) and the input of the movement command is again judged. If the result of the movement command input determination is NO, the determination is repeated until YES is passed.

If the input determination of the movement command is YES, as shown in FIG. 5, the processing of the left copying traveling or the right copying traveling is performed, and the copying traveling completion signal is sent from the welding robot control panel to the movement control panel (10). Is output to.

Next, the operation of welding the welded portion of the hull block shown in FIG. 13 will be specifically described with reference to the flow chart of FIG. 6 and the operation explanatory diagrams of FIGS. 7 and 8. .

First, set the welding robot (1) together with the base (2) at any position on the skin (S) which is the horizontal base material, and turn on the ready key of the keyboard (15), and then the CPU (18) causes the panel The ready key ON is read through the interface circuit (16), and immediately the CPU (18) completes the welding robot control panel (12) via the I / O interface circuit (19). A signal is output, and by inputting this ready signal,
As shown in FIG. 7 (a), the manipulator (1) is connected from one of the intersecting vertical base materials, the transformer (T) and the longitudinal (L).
The position information of the unit work origin P1 given as a distance (X1, Y1) less than the maximum operation distance in b) and the right origin alignment signal are
Output from the welding robot control board (12) to the movement control board (10).

Then, the digital servo circuit (20) by the CPU (18),
Software servo control via the pulse generators (21c) and (21d) changes the state shown in Fig. 8 (a) to that of Fig. 8 (b).
In order to rotate the wheels (4a), (4b) by 90 °, the servomotors (5a), (5b) are appropriately rotated, and in this state, the third and fifth sensors (8c), (8e), A / D conversion unit
(11), via the interface circuit (14), FIG. 7 (b)
As shown in, the distance l between the sensor (8c), (8e) and the transformer (T)
3, l4 is read by the CPU (18) and this distance l3, l4
As feedback information, l3 = l4 = X1−w / 2 (where w is the width of the base (2))
The a) and (6b) are appropriately rotated by software servo control, and the base (2) is controlled parallel to the longe (L).

Next, the CPU (18) rotates the servomotors (5a) and (5b), and the wheels (4a) and (4b) are rotated by 90 ° as shown in FIG. 8 (c). , The CPU (18) rotates the servomotors (6a), (6b) toward the unit work origin P1 shown in FIG. 7 (b), and the operation center point M of the manipulator (1b) reaches the work origin P1. Until the base (2) runs.

At this time, while the base (2) is running, the CPU (18) causes the fifth
Through the sensor (8e), the A / D conversion unit (11), and the interface circuit (14), as shown in FIG.
The distance l5 between e) and longe (L) is read, and l5 = Y ₁ -D
(However, when D is the distance from the sensor (8e) to the operation center point M of the manipulator (1b)), the wheels (4a), (4
The drive of b) is stopped, and the base (2) is stopped in a state where the operation center point M and the unit work origin P1 match.

Then, in this state, the wheels (4a), (4b) are fixed by the servo lock by the CPU (18), and the positioning completion signal is sent to the welding robot control board (12) via the I / O interface circuit (19). By output of this positioning completion signal, according to the unit work program stored in advance,
The welding robot control panel (12) controls the welding robot (1), and as shown in FIG.
(T), unit welding work is performed on the corner portion of the welded portion of the longe (L) and the skin (S).

Further, when the above-mentioned first unit welding work is completed, the welding robot control panel (12) outputs the left origin alignment signal, and as shown in FIG. 7 (d), the other transformer (T) and Unit work origin P given as distance (X2, Y1) from the longe (L) to the maximum operating distance of the manipulator (1b) or less
The position information of 2 is output to the movement control panel (10), and the CPU
As shown in FIG. 8 (d), the directions of the wheels (4a), (4b) are rotated by 90 ° by (18), and the base (2) is moved to the second unit work origin P.
After traveling toward 2, the distances l1 and l2 between the fourth and first sensors (8d) and (8a) and the transformer (T) are changed to l1 as shown in FIG. 7 (e).
When = l2 = X2-w / 2, the wheels (4a) and (4b) are stopped, and the base (2) is stopped in a state where the operation center point M and the unit work origin P2 coincide with each other.

At this time, as shown in FIG. 8 (e), the directions of the wheels (4a), (4b) are further rotated by 90 °, and the fifth sensor (8e) and the longitudinal
The distance l5 from (L) is finely adjusted so that l5 = Y1-D, and after the fine adjustment, the wheels (4a) and (4b) are fixed by the servo lock of the CPU (18), and the I / O Through the interface circuit (19), the positioning completion signal is output to the welding robot control panel (12), by the input of this positioning completion signal, according to the unit work program stored in advance,
The welding robot control panel (12) controls the welding robot (1), and as shown in FIG. 7 (f), one of the longes (L),
A unit welding operation is performed on the corner of the welded portion between the other transformer (T) and the skin (S).

When the second unit welding work described above is completed, the welding robot control panel (12) controls the welding robot (1) so that the welding torch (1c) has the optimum posture and position, and then the left side. Copy travel command, travel distance L1, travel speed V1
While being output from the welding robot control panel (12) to the movement control panel (10), an arc start signal is output to a welding power source (not shown) via the welder interface unit (13).

Next, while the base (2) travels approximately parallel to the other transformer (T) while maintaining the state shown in FIG. 7 (f), a straight line between the transformer (T) and the skin (S). -Shaped welding of the welded part is stopped, and the copy-running completion signal is sent to the welding robot control panel.
The signal is output to (12), and the arcing is immediately stopped by the welding robot control board (12) by this copying traveling completion signal, the welding robot (1) is controlled, and the original posture is restored.

Further, in the same manner as the above-mentioned operation, FIG.
As shown in (l), the postures of the robot (1) and the base (2) are reversed, and the other transformer (T), the other longe (L), one transformer (T) and the skin (S) The welding of the corners and the straight portions of the welded portion of 1 is completed, and the welding of the welded portion of one hull block is completed.

As the work origin at this time, as shown in FIG. 7 (h), a point P3 given as a distance (X3, Y2) from the other transformer (T) and the other longe (L) is set. At the same time, as shown in FIG. 7 (j), a point P4 given as a distance (X4, Y2) from one transformer (T) and the other longe (L) is set.

Next, the above-described left contour traveling process will be described with reference to the flow chart of FIG.

Before the left copying traveling routine shown in FIG. 9 is executed, the data of the traveling distance L1 and the traveling speed V1 are output from the welding robot control panel 12 and stored in the RAM (17). When the routine is executed, the motors (6a), (6
b) is It is rotated at the rotation speed n1 given by.

Then, the pedestal (2) starts traveling, but since there is no track and it is not in contact with the transformer (T), the parallel line with the transformer (T): the side opposite to the transformer (T) than Pl1 or the transformer (T). (8a), (8c) because it is naturally expected to deviate to the () side.
Distance l1 between the base (2) and the transformer (T) measured by
The deviation amount Δl is obtained from l2, and then the deviation direction is determined.

First, when there is no deviation and when the deviation is the first reference value | ±
In the case of lk1 | or less, steering is not performed.

Next, when the base (2) is deflected to the side opposite to the transformer (T), + θk1, and when it is deflected toward the transformer (T), −θk.
When the motors (6a) and (6b) are controlled by k1 and the wheels (4a) and (4b) are rotated, and the deviation is less than or equal to the second reference value | ± lk2 |, that is, In the case of, the motors (6a) and (6b) are rotated at an angular velocity of ωk1, and when the deviation amount is larger than the second reference value | ± lk2 |, they are rotated at an angular velocity of ωk2.

Therefore, the deviation amount Δl, the steering angle θ and the steering angular velocity ω
Fig. 10 (a) shows the relationship with the above. In this way, control is performed until the traveling distance becomes equal to the command value L1, and the traveling locus Q of the operation center point M is shown in Fig. 10. As shown in (b), the maximum deviation A1 is the welding robot.
The reference constants lk, θk, and ωk are obtained in advance by experiments or the like so that they do not hinder the implementation work of (1), and are ready for practical use.

On the other hand, the operation of the right copying traveling process is also performed in the same manner as the left copying traveling process described above, as shown in the flow chart of FIG. 11, and the deviation amount Δl at that time and the steering angle θ and the steering angular velocity ω are The relationship is as shown in Fig. 12 (a), the running locus Q of the operation center point M is as shown in Fig. 12 (b), and the maximum deviation A2m is used for the welding robot (1) implementation work. The reference constants lk, θk, ωk are obtained in advance so as not to cause any trouble so that they can be put to practical use.

Therefore, according to the embodiment, each sensor (8a) ~ (8e)
When the angle of the welded portion is welded, the position of the operation center point M of the manipulator (1b) of the welding robot (1) is controlled to coincide with the work origins P1 to P4 by the detection signal from At the time of welding, the operation center point M is maintained at a constant distance from the transformer (T) which is the vertical base metal, and the base (2)
Since the traveling is controlled, the position of the welding robot (1) can be automatically controlled, and the skin (S) that is the horizontal base material and the transformer (T) and the longe (L) that are the vertical base materials that form the peripheral surface. It is possible to automatically and efficiently weld the welded part with.

The number of distance sensors is not limited to five.

〔The invention's effect〕

As described above, according to the position controller for the welding robot of the present invention, the position of the welding robot can be automatically controlled by the detection signal from each distance sensor, and the horizontal base metal can be used like a hull block. It is possible to automatically and efficiently weld the welded part to the vertical base metal forming the peripheral surface.

[Brief description of drawings]

1 to 12 show an embodiment of a position control device for a welding robot according to the present invention. FIGS. 1 to 3 are front views, plan views and right side views of the external appearance, and FIG. Circuit block diagrams, FIGS. 5 and 6 are flow charts for explaining the operation, FIGS. 7 (a) to 7 (l) are operation explanation diagrams of the position control of the base, and FIGS. 8 (a) to 8 (e) are FIG. 9 is a flow chart for explaining the operation of the direction control of the wheels, FIG. 9 and FIG. 11 are flow charts for explaining the operation at the time of left profile traveling and right profile traveling, FIG. 10 (a), (b) and FIG.
(a) and (b) are operation explanatory views during left profile traveling and right profile traveling, respectively. (a) is a diagram showing the relationship between the reference constants, and (b) is the traveling of the center point of motion. FIG. 13 is a perspective view of a general hull block showing the trajectory. (1) ... Welding robot, (1b) ... Manipulator, (2) ... Base, (4a), (4b) ... Wheels, (5a), (5b), (6a), (6b) ... Motor,
(8a) to (8e) ... First and fifth sensors, (S) ... Skin, (T) ...
Transformer, (L) ... Longe, M ... Operation center point, P1-P4 ... Work origin.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Yoshito Mihara 1-6-14 Edobori, Nishi-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. (72) Inventor Shigeo Mogi 1-3-3 Sakurajima, Konohana-ku, Osaka, Osaka No. 4 inside High System Control Co., Ltd.

Claims (1)

[Claims] 1. A welding robot position control device for controlling the position of a welding robot for welding a welded portion of a horizontal base material and a vertical base material forming a peripheral surface, comprising a base on which the welding robot is mounted, A plurality of wheels rotatably provided on the base, a plurality of non-contact type distance sensors provided on the base to detect a distance from each of the vertical base materials and output a detection signal, When welding a corner of a welded portion, the detection signal is used to derive a deviation between the working origin of the robot manipulator less than or equal to the maximum operation distance and the operation center point of the manipulator, and the wheel is moved to make the deviation zero. Derivation means for deriving the direction and the amount of rotation, driving means for driving the rotation amount in the moving direction in which the wheel is derived, and at the time of welding the straight portion of the welded portion, from the vertical base metal by the detection signals. The movement Position control device of the welding robot, characterized in that the distance to the center point and a scanning control means for controlling the wheel so as to be constant.