JPH08103870A - Welding robot - Google Patents

Abstract

PURPOSE: To prevent the defective welding by scanning the part to be welded, calculating the deviation from the reference position, and correcting the teaching data to achieve the welding, or transmitting the re-sensing order to achieve the scanning again, and dealing with the error after confirmation of the order when the deviation meets the predetermined error condition. CONSTITUTION: A sensor 21 is scanned in the teaching mode to prepare the teaching data, and the data are stored in a storage part 13b. The part to be welded of a work is scanned in the feedback mode, comparison is made with the teaching data, and a deviation calculating part 13c calculates the deviation. A correcting part 13d corrects the teaching data according to the deviation, and outputs the corrected data to a robot controller 12 to achieve the welding. When an error judging part 13e makes a judgement that the deviation meets the predetermined error condition, the instruction is made to a sensing re-try command part 13g to achieve the scanning again. When the cause of the error is eliminated as the elapse of time, the error does not becomes an official error, and the treatment is progressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a sensor with a welding torch on the distal wrist of a moving arm, and the sensor senses the shape (including the position) of the planned welding site and uses the sensing data in advance. The present invention relates to a teaching playback type arc welding robot (hereinafter, simply referred to as a welding robot) that performs welding while correcting taught data.

[0002]

2. Description of the Related Art Conventionally, as a welding robot of this type,
For example, JP-A-5-212540 and Japanese Patent Application No. 6-1
There is one described in Japanese Patent No. 6293. In such a welding robot 1, as shown in FIG. 9, the laser sensor 4 and the welding torch 5 are arranged on the tip wrist of the movable arm 3 arranged on the pedestal 2. The laser sensor 4
Is arranged so that it can be scanned with a laser beam along a detection line in a direction orthogonal to the direction of the planned welding line in the vicinity of the welded portion, and a part of the laser diffused light diffusely reflected on the surface of the workpiece during scanning is The light is received and the shape such as the position of the planned welding site is detected.

In this welding robot 1, as shown in the figure, first, the teaching (teaching) mode is set, the movable arm 3 is directed toward a teaching object 7'of the same size and size as the object 7 to be welded, and the robot body ( The controller 6 for controlling the manipulator) learns and stores in advance a welding reference position for welding and a sensor measurement position for performing measurement by scanning with the laser sensor 4. After that, the movable arm 3 is directed to the workpiece 7 on the feed line L in the playback mode, and the planned welding position of the workpiece 7 is stored based on the stored welding reference position and sensor measurement position. Deviation is detected to create position correction data, and based on this position correction data, the controller 6 corrects the position difference between the stored welding reference position and the detected planned welding position, and the workpiece is welded. The welding torch 5 welds to the welding scheduled portion 8 of 7. According to the welding robot having such a configuration, it is possible to perform welding faithfully to the teaching content at an accurate welding position for an object to be welded that is difficult to be repeatedly positioned at an accurate position.

[0004]

By the way, when the laser sensor senses the planned welding site of the object to be welded, erroneous data may be sent to the controller for some reason. In this case, if the teaching data is corrected as it is based on the data from the laser sensor and welding is performed, there is a possibility that welding failure may occur or the welding torch may hit the workpiece. However, if the laser sensor data is not available (this is called an error)
Of the above, if the cause of the error is resolved naturally over time, for example, if the vibration caused when the work piece is set on the fixture is the cause of the error, By repeating the sensing, the error is resolved and correct detection data can be obtained. Therefore, when it is found that an error has occurred, the operator needs to perform an operation of returning the program so as to execute sensing again, but in such a case, the operation is troublesome because it is a manual operation.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a welding robot which can automatically perform another sensing when a sensing error occurs.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 has a robot main body provided with a welding torch at a tip of a moving arm and a sensor for measuring a surface position of a planned welding site. And a robot control means for controlling the operation and welding operation of the moving arm portion of the robot body, and when a sensing command is input, issues a movement command to the robot control means to position the moving arm portion at a sensing position, Sensing control means for scanning the sensor in the direction orthogonal to the planned welding line of the planned welding site with the moving arm positioned at the sensing position, and correction for correcting data taught in advance based on the data of the sensor A welding robot that controls the robot body according to the output of the correction means, wherein the robot control means includes:
Error determination means for determining abnormality of the sensor data or data obtained by processing the data, and sensing retry command means for sending a sensing command again to the sensing control means when the error determination means determines an error. It is characterized by having.

According to a second aspect of the present invention, there is provided the welding robot according to the first aspect, wherein when the sensing retry command means issues a sensing command a predetermined number of times and the error determination means determines that there is an error, an error signal is output. An error signal generating means for sending to the robot control means is provided.

According to a third aspect of the present invention, in the welding robot according to the second aspect, the error determination means determines which of a plurality of error conditions given in advance corresponds to the error condition, Error signal generating means, among the different error signals corresponding to each of the above error conditions,
It is characterized in that an error signal corresponding to a corresponding error condition is sent to the robot control means.

[0009]

When the sensing command (first time) is input, the sensing control means sends a movement command to the robot control means, and the robot control means moves the moving arm portion in response to the movement command. , Position the sensor at the sensing position. Upon positioning, the sensing control means causes the sensor to scan in a direction orthogonal to the planned welding line, and the sensor accordingly detects the shape of the planned welding part. Then, the correction means corrects the data taught in advance by the shape data. The corrected teaching data is sent to the robot control means, and the robot control means controls the robot main body based on the corrected teaching data to execute welding.
In this case, if an abnormality in the sensor data or the processed data is confirmed during sensing, the sensing retry command means automatically issues the sensing command again,
In response to this, the sensing control means performs processing to perform sensing again.

According to the second aspect of the present invention, when the sensing error is not resolved even after the sensing is performed again a predetermined number of times, the error signal is sent to the robot control means only at that time.

According to the third aspect of the invention, when a formal error is recognized, different error signals are sent to the robot control means according to the content of the error, so that the robot control means can deal with each error.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of an entire welding robot system according to an embodiment of the present invention, and FIG. 2 is a block diagram showing an electrical configuration of a sensor controller applied to the system. The welding robot of this example is installed in an assembly plant of a steel frame type building unit, and performs arc welding of steel beams and columns of a structure temporarily assembled on a feed line via a joint piece. As shown in FIG. 1, the robot main body 11, a robot controller (robot control device) 12, a sensor controller 13, a display device (monitor) 14, and a teaching box 15 are provided. Or host computer is connected.

The robot body 11 has a multi-joint structure in which a motor and a speed reducer are directly attached to each joint, and the base 2
A moving arm portion 16 that can be driven three-dimensionally and can take a desired posture is provided on the above. The moving arm portion 16 includes two arms (a first arm 17a and a second arm 17b), a movable arm 17 that can be driven in a predetermined direction, and a wrist portion 18 provided at the tip of the movable arm 17. The movable arm 17 includes a base portion 19 which rotatably supports the base end portion of the movable arm 17 on the pedestal 2 and drives the movable arm 17 to reciprocate between the object to be welded and the teaching object. The wrist 18 is provided with a welding torch 20 and a laser sensor 21 for detecting the shape of the planned welding site and the position of the planned welding line.

FIG. 3 is a partial perspective view showing an example of an object to be welded 50 which is a structure. In this example, the object to be welded 5
Reference numeral 0 is a part of the steel frame of the building unit, which is a column 51 made of a rectangular steel pipe with an R portion at each corner, and a joint piece 5 arranged close to the upper end or the lower end of the column 51.
2 and the edge portion 52a of the joint piece 52
However, they are temporarily attached in advance to the corners of the columns 51 with a gap of about several mm. And this joint piece 52
A welding planned line P for arc welding is set along the edge portion 52a so as to join the edge portion 52a and the corner portion of the column 51.

The joint piece 52 is a joining member having a U-shaped cross section for joining the beam to the column 51 to construct it.
When arc welding the joint piece 52 and the pillar 51, the beam has already been inserted into the U-shaped recess of the joint piece, and the double-structured portion has been spot-welded and fixed to each other. There is. That is, after the steel skeleton of the building unit is temporarily assembled on the feed line, the corners of the steel skeleton (the joints between the upper and lower ends of the pillar 51 and the joint piece 51) are main welded by the welding robot of this example. The Rukoto.

The laser sensor 21 is provided with a light emitting section including a semiconductor laser and a light projecting lens, and a light receiving section including an image forming lens, a position detecting element (PSD), and the like, and the light emitted from the semiconductor laser is projected. When a beam spot is created on the DUT by the optical lens, the beam spot is diffusely reflected (diffuse reflected) on the DUT surface, and a part of it returns to the position on the position detection element by the imaging lens. The image of the spot light and the distance from the front surface of the laser sensor 21 to the surface of the object to be measured can be measured. The laser sensor 21 is provided so as to be capable of scanning in the direction of the detection line S near the planned welding line P.
The surface position of the workpiece 50 along the detection line S is detected. The scanning mechanism of the laser sensor 21 may be one that drives the laser sensor 21 itself.
Inside the laser sensor 21, a mirror or the like may be used to change the irradiation direction of the light from the light emitting unit.

A sensor controller 13 is connected to the laser sensor 21. As shown in FIG. 2, the sensor controller 13 includes a sensing drive circuit 13a.
A shape analysis unit 13b, a storage unit 13c, a deviation amount calculation unit 13d, a correction unit 13e, an error determination unit 13f,
It is electrically configured by a sensing retry command unit 13g, an error signal generation unit 13h, a teaching data creation unit, an optimum condition selection unit, a transmission circuit, and a control unit (all not shown).

In the sensor controller 13, the sensing drive circuit 13a issues a command to the robot controller 12 to move the front surface of the laser sensor 21 to the sensing position by a sensing command input according to the start operation, and the front surface of the laser sensor 21 is sensed. It is a circuit for scanning the laser beam (spot light) in a direction orthogonal to the planned welding line of the planned welding site in the state of being positioned. The shape analysis unit 13b, based on the detection signal sent from the laser sensor 21 and according to a predetermined algorithm, the dimensions of the gap, step, etc. of the welding site of the workpiece 50 and the position of the edge 52a (in this example). Then, the shape data such as the position of this edge becomes the planned welding position) is calculated. The teaching data creation unit (not shown)
In the teaching mode, the laser sensor 21 is scanned to create teaching data including the shape data of the simulated welding site,
The data is stored in the storage unit 13b including a RAM and an EEPROM.

In addition to storing the teaching data, the storage section 13c scans the laser sensor 21 and stores the amount of received light measured at each measurement point. In addition, the deviation amount calculation unit 13d
Is the reference position (the position of the edge portion 52a ′ taught by the teaching object 50 ′) included in the teaching data and the planned welding position (edge portion 52a) of the workpiece 50 analyzed by the shape analysis unit 13b.
Position) is calculated. The correction unit 13e corrects the teaching data based on the output of the deviation amount calculation unit 13d. The optimum condition selection unit (not shown) selects the optimum welding condition according to the corrected teaching data from the optimum welding condition database stored in advance by the robot controller 12.

Further, the error determination section 13f determines whether or not the signal from the laser sensor 21 or the shift amount calculation section 13d satisfies a predetermined error condition. In addition, the sensing retry command unit 13g uses the error determination unit 1
If 3f is determined to be an error, the sensing command is sent again to the sensing drive circuit. Error signal generator 1
3h generates an error signal when the error determination unit determines that there is an error even if the sensing retry command unit issues a sensing command a predetermined number of times. Also, a transmission circuit (not shown)
Transmits to the robot controller 12 the coordinate values of the planned welding site (corrected teaching data), the optimum welding condition signal, and the error signal. The control unit includes a CPU (central processing unit) and internal memories such as ROM and RAM, and
By executing the processing program stored in the OM using the RAM, each component of the sensor controller 13 is controlled.

The error determination section 13f in this example can determine which of a plurality of error conditions given in advance corresponds to the error condition. Then, the error signal generating unit 13h generates an error number (different for each error condition) corresponding to the corresponding error condition. In particular, when the error determination unit 13f determines that a plurality of error conditions are satisfied, the error signal generation unit 13h is configured to generate only an error number corresponding to a higher-order error condition having a predetermined priority. The specific relationship between the error condition and the error number will be described in the description of the operation.

The sensor controller 13 is connected to the robot controller 12. When the robot controller 12 receives a movement command to the sensing position from the sensor controller 13, the robot controller 12 moves the moving arm 16 to position the laser sensor 21 at the sensing position. In addition, the robot controller 12 controls the operation of the robot main body 11 based on the corrected teaching data (corrected coordinate values of the planned welding site), the optimum welding condition signal, etc. sent from the sensor controller 13, and performs welding. To execute. When an error signal is sent, the error signal is displayed on the display device 14, and the operation of the robot main body 11 is stopped if necessary. The optimum welding condition database in the robot controller 12 stores information such as current, voltage, speed, torch angle, and aiming angle for determining welding conditions based on the knowledge and experience of skilled workers.

Next, the operation of this example will be described. In the assembly plant of the building unit, the welding robot uses this welding robot to weld the planned welding site (column 51) of the workpiece 50.
And the joint piece 52), first, the teaching object is arranged outside the feed line so that the relative position with respect to the robot body 11 has the same relationship as the object to be welded on the feed line. . The teaching material is the same as the work piece or a modeled one. Then, the robot main body 11 is directed to this teaching object to perform teaching. That is, first, the welding robot 10 is taught the reference coordinates of the teaching object by moving the tip of the movable arm 17. Then,
By manually moving the tip of the welding torch 20 along the simulated welding planned line of the teaching object, the coordinate value of the moving arm portion 16 is detected and the welding reference line is calculated.

Next, the sensing position (laser sensor 21
Measurement position) is determined, the laser sensor 21 is scanned at that position, and the shape of the simulated welding site is analyzed by the measurement data. The analysis data includes the coordinate value of the edge portion (welding reference position) of the teaching object and the coordinate value of the welding reference line. In the case of this example, the sensing positions are two points that are vertically spaced (three points or more may of course be used). Next, the movable arm 17 of the robot body 11 is returned to the object to be welded 50 on the feed line to enter the regeneration mode, and the automatic welding process is started. When the start operation is performed, first, the sensing command is sent together with the start signal to the sensor controller 13
And the sensor controller 13 side starts its own processing as shown in FIG. At the same time, the robot controller 12 side also starts its own processing as shown in FIG.

The operation will be described below with reference to the flow charts shown in FIGS. FIG. 4 shows a processing flow on the robot controller 12 side, and FIG. 5 shows a processing flow on the sensor controller 13 side. The sensor controller 13 appropriately sends a movement command to the robot controller 12 side, and as shown in FIG.
The laser sensor 21 is positioned at 1 and SP2, and the laser sensor 21 is positioned at the respective sensing positions SP1 and SP2.
To be scanned (h in the figure indicates the scanning range), and the workpiece 5 is welded.
Positions S1 and S2 of zero edge portion (scheduled welding position) 52a
To analyze.

That is, on the sensor controller 13 side,
As shown in FIG. 5, a movement command to the sensing position SP1 is transmitted in step S201. At this time, the coordinate values in the work space are calculated using only the coordinate values of the movable arm 18 and the wrist 19 among the coordinate values when the teaching is performed toward the teaching object. The laser sensor 21 is moved to the sensing position SP1 of the object to be welded 50 on the feed line, excluding the coordinate values of the base portion 20 used for the reciprocal movement between the object to be welded 50. Then, in step S202, it is confirmed whether or not the laser sensor 21 has arrived at the sensing position SP1. If it is confirmed that the laser sensor 21 has arrived, in step S203, the laser sensor 2 is detected.
1 is scanned along the inspection line S to perform sensing. Then, in step S204, a command to move to the sensing position SP2 is transmitted, and similarly in step S205.
When it is confirmed that the laser sensor 21 has arrived at the sensing position SP2 in, the sensing is executed in step S206. Then, when the sensing at the two locations is completed, in step S207, the welding data of the workpiece 50 (including the coordinate value of the planned welding site, the welding conditions, etc.) is calculated based on the collected data of the laser sensor 21.

In step S207 for calculating the welding data, as shown in FIG. 8, the amount of deviation between the position of the edge portion 52a 'analyzed by the teaching object 50' and the position of the edge portion 52a analyzed by the object 50 to be welded. δ is calculated, the larger deviation amount δ between the upper and lower sensing positions SP1 and SP2 is selected, and the content of the teaching data is corrected according to the deviation amount δ.
The corrected data is used as the official coordinate data of the planned welding site. Also, the optimum welding conditions are determined based on the shape data and the like. On the other hand, as shown in FIG. 4, the robot controller 12 side moves the moving arm 16 to position the laser sensor 21 at the sensing position SP1 when a movement command to the sensing position SP1 is received, and when the positioning is performed, an arrival signal is sent to the sensor controller. Send to 13.

Similarly, when a command to move to the sensing position SP2 is received, the moving arm portion 16 is moved to position the laser sensor 21 at the sensing position SP2, and upon positioning, an arrival signal is transmitted to the sensor controller 13. On the sensor controller 13 side, when the calculation of the welding data in step S207 is completed, the process proceeds to step S208, and it is determined whether or not the calculated welding data has an error. Here, even if the measurement by the laser sensor 21 is impossible, it is determined as an error.

This sensing error is judged by an error diagnosis function provided in the sensor controller 13 depending on whether or not the following error condition (diagnosis condition) is met. (1) The position S1 of the edge portion at the sensing position SP1 cannot be measured. (2) The position S2 of the edge portion at the sensing position SP2 cannot be measured. (3) The difference (deviation amount δ) between the position of the edge portion of the teaching data and the position S1 of the edge portion of the workpiece is not less than the predetermined value L1. (4) The difference (deviation amount δ) between the position of the edge portion of the teaching data and the position S2 of the edge portion of the workpiece is not less than the predetermined value L1. (5) The difference between S1 and S2 exceeds the predetermined value L2.

When the above error conditions are not satisfied, it is determined that there is no error, a welding determination signal is transmitted in step S209, welding data is transmitted in step S210, and a welding start command is transmitted in step S211. Then, in step S212, the process is terminated after waiting until it is confirmed that the welding end signal is received.

On the other hand, if the above-mentioned error condition is satisfied, it is judged that there is an error in step S208,
In step S213, the sensing retry determination signal is transmitted to the robot controller 12 here. If the number of sensing retries is 3 or less, the determination in step S241 becomes NO and the process returns to the first step S201 to re-execute the sensing operation. If the number of sensing retries exceeds three times, the determination in step S241 becomes YES, a welding non-determination signal is transmitted in step S215, an error number is transmitted in step S216, and the process is ended.

The error number in this case is set corresponding to each error condition, and is associated with each error condition as follows. Error number ... Error content 31 ... (1) 32 ... (2) 33 (*) ... (3) 34 (*) ... (4) 35 (*) ... (5)

Therefore, when an error corresponding to the above condition (2) occurs, the error number "32" is transmitted to the robot controller 12. When a plurality of errors occur simultaneously, the error number is sent at the same time. However, if there is a priority, only the error number with the higher priority is transmitted. Here, the error with the number without * is higher than the error with the number with *. Therefore, even if the error marked with * is detected, if the error number “31” or “32” occurs, the number marked with * is not transmitted.

On the robot controller 12 side, when a sensing retry determination signal is transmitted, step S
The determination of 107 is YES, and the process returns to step S101 to enter the sensing operation acceptance state. If the sensing retry determination signal is not sent, step S
The process proceeds from step 107 to step S108, and it is determined whether the welding determination signal has been transmitted. If the welding determination signal is transmitted, the process waits for the welding data to be transmitted in step S109. When the welding data is transmitted, it is received in step S110. Then, in step S111, the process waits for a welding start command to be transmitted. If a welding start signal is transmitted, step S11
When welding is executed in step 2 and the welding is completed, step S11
At 3, the welding end signal is transmitted to the sensor controller 13.

When it is determined in step S108 that the welding determination signal has not been transmitted, the process proceeds to step S114, in which it is determined whether or not the welding non-determination signal has been transmitted. If NO, the process returns to step S107. If the welding non-determination signal is transmitted, the determination in step S114 is YES, and the error number is received in step S115. When the error number is transmitted, the robot controller 12 displays the number on the display device and stops the operation of the robot body.

As described above, when the sensing error occurs, the sensing operation is performed again, so that it is not necessary to manually perform the sensing again. Therefore, if a sensing error occurs due to vibrations that are resolved over time, such as vibrations when setting the workpiece, the error will automatically occur when the vibrations subside. The teaching data is corrected on the basis of the data that is eliminated and is correctly detected by the laser sensor 21, and welding is performed at the correct welding planned position.

Further, since the error signal is transmitted to the robot controller 12 side only when the sensing is re-executed several times and the error is still not resolved, if the cause of the error is resolved over time, Processing proceeds without a formal error. Further, since the error signal is sent to the robot controller 12, the robot controller 12 can immediately deal with it. Therefore, there is no concern that welding will be performed due to erroneous sensing data, and there is no risk of causing welding defects or hitting the welding torch 18 on the workpiece 50. Further, by looking at the display screen, it is possible to know what error has occurred, so that the error can be dealt with immediately. In particular, since only errors with higher priority are displayed, it is possible to efficiently eliminate the errors by coping with the displayed contents.

The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific structure is not limited to this embodiment, and there are design changes and the like within a range not departing from the gist of the present invention. Also included in the present invention. For example, in the flowchart of FIG. 5, the error number is generated at the same time prior to the transmission in step S216, but the error number itself is generated during the calculation of the welding data in step S207, and the welding is performed at this point. An error number is set instead of the data, the presence or absence of the error number is checked in step S208, and if the error number does not disappear after three sensing retries in step S216, the error number is transmitted to the robot controller 12. You may.

Further, the error condition is not limited to the above example, but various settings can be made. The error number can also be set to any sentence number. The number of sensing retries is not limited to three,
It can be set arbitrarily. Further, the sensor controller does not matter whether it has a software configuration or a hardware configuration. Further, in the above-described embodiment, the case where the sensor controller and the robot controller are separate from each other has been described. However, for example, the robot controller may also have the function of the sensor controller.

[0040]

As described above, according to the first aspect of the invention, when the sensing error is detected, the sensing operation is performed again, so that it is not necessary to manually perform the sensing again. Therefore,
In particular, if a sensing error occurs due to vibration that is resolved over time, such as vibration when setting the workpiece, the error is automatically resolved by re-sensing after the vibration has subsided. Then, the teaching data is corrected based on the data correctly detected by the sensor, and the welding is performed at the correct welding planned position.

According to the second aspect of the invention, when a sensing error occurs, the sensing is re-executed several times,
If the error is still not resolved, the error signal is generated for the first time. Therefore, if the cause of the error is resolved with the passage of time, the process proceeds without a formal error. Therefore, in the case of an error due to vibration at the time of setting the object to be welded, the vibration is automatically resolved as the vibration subsides, and the welding is executed as it is. Further, in the case of an error whose cause cannot be resolved even with the passage of time, an error signal is generated, so that the occurrence of the error can be known.

According to the third aspect of the present invention, since the signal corresponding to the corresponding error condition is sent to the robot control means, the robot control means can execute the coping method according to the content of the error. it can.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing an electrical configuration of a sensor controller applied to the system.

FIG. 3 is a diagram for explaining how the sensor mounted on the welding robot senses a planned welding site of the workpiece.

FIG. 4 is a flowchart showing a control processing procedure on the robot controller side of the embodiment.

FIG. 5 is a flowchart showing a control processing procedure on the robot controller side of the embodiment.

FIG. 6 is a flowchart showing a control processing procedure on the sensor controller side of the embodiment.

FIG. 7 is a flowchart showing a control processing procedure on the sensor controller side of the embodiment.

FIG. 8 is a plan view for explaining the positional deviation of the edge portion between the teaching object and the object to be welded according to the same embodiment.

FIG. 9 is a plan view showing a schematic configuration of a conventional welding robot.

[Explanation of symbols]

 10 welding robot 11 robot body 12 robot controller (robot control means) 13 sensor controller 13a sensing drive circuit 13b shape analysis unit 13c storage unit 13d deviation amount calculation unit 13e correction unit 13f error determination unit 13g sensing retry command unit 13h error signal generation unit 14 Display Device 15 Teaching Box 16 Moving Arm 20 Welding Torch 21 Laser Sensor 50 Workpiece

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G05B 19/42

Claims (3)

[Claims] 1. A robot main body having a welding torch at a tip of a moving arm portion and a sensor for measuring a surface position of a planned welding site, and a robot control means for controlling the movement and welding operation of the moving arm portion of the robot main body. When a sensing command is input, a movement command is issued to the robot control means so as to position the moving arm portion at the sensing position, and the sensor is welded to a welding target portion while the moving arm portion is positioned at the sensing position. The robot is provided with a sensing control means for scanning in a direction orthogonal to the planned line and a correction means for correcting data taught in advance based on the data of the sensor, and the robot control means responds to the output of the correction means. In a welding robot for controlling the main body, an error determination means for determining an abnormality in the data of the sensor or the data obtained by processing the sensor, If the error determination means determines that the error, welding robot, characterized in that a sensing retry command means for sending a re-sensing instruction in the sensing control means. 2. The welding robot according to claim 1, wherein an error signal is sent to the robot control means when the error determination means determines that there is an error even when the sensing retry command means issues a sensing command a predetermined number of times. A welding robot, characterized in that it is provided with error signal generating means. 3. The welding robot according to claim 2, wherein the error determination means determines which one of a plurality of error conditions given in advance corresponds to the error condition, and the error signal generation means, Among the different error signals corresponding to each of the error conditions, an error signal corresponding to the corresponding error condition is sent to the robot control means.