JPH06149327A - Real-time position correcting method - Google Patents

Abstract

PURPOSE:To attain the accurate correction of positions of such job means like a welding torch, etc., by storing the measurement data on a laser sensor and correcting the position error of a work means or a work subject based on the measurement data when the position set on the work subject is coincident with the work means. CONSTITUTION:A work subject is set in its moving direction and in the offset direction of a laser sensor 4. Thus the position of the subject is measured before the position set on the subject is coincident with a work means and this measurement data is stored. The position error of the work subject or the work means is corrected based on the position set on the subject. Thus it is possible to accurately correct the position error between the work subject and the work means regardless of the individual difference of the welding lines, the sealing lines, etc., of the work subject and the offset value caused between the work means and the sensor 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an improvement of a position correction method,
In particular, the present invention relates to a real-time position correction method for correcting the positional deviation between the moving work object and the work means in real time.

[0002]

2. Description of the Related Art By detecting the position of a welding line or a sealing line with a laser sensor, a positional deviation between a work object fixed at a fixed position and a work means such as a welding torch attached to the tip of a robot hand is detected. A position correction method for correcting is known.

Further, as a laser sensor used for such position correction work, a oscillating mirror for beam scanning, a light receiving element for detecting reflected light, and an optical system are provided.
A feature is that the distance between the laser sensor and the work object is detected by the scanning operation of the beam, and the position of the welding line or sealing line is detected by obtaining the cross-sectional data of the work object orthogonal to the scanning direction. Wishhei 3-
It has already been proposed as No. 165038, Japanese Patent Application No. 3-240473 and the like.

In the conventional welding work or sealing work, a working means such as a welding torch or a laser sensor is attached to the tip of the robot hand, and the position of the welding line or the sealing line is determined from the sectional data of a plane orthogonal to the moving direction of the robot hand. Therefore, the positional deviation of the tip of the robot hand, that is, the working means such as the welding torch is corrected by comparing the obtained position data with the position data at the time of teaching.

[0005]

However, when a welding work or a sealing work is attempted by moving only the robot hand along the outer circumference of a work object having a circular column shape or a circular ring shape while fixing the work object, the robot itself has a constant inclination arc. Even if functions such as control are provided, it is difficult to move the tip of the robot hand to the back side of the work target to maintain the posture, and it becomes impossible to continuously perform a series of welding or sealing work. There are cases. In addition, when handling a work object with a long span, if the work is performed while moving the robot arm while the work object is fixed, the work area is limited by the operable range of the robot, and all work cannot be performed at once. Sometimes.

Therefore, it is desired to perform welding, sealing, and other operations by rotating or moving the side of the work object, which is composed of a cylinder, an annular ring, or the like, without significantly changing the position or posture of the robot. However, if a welding operation or a sealing operation is to be performed by a teaching operation in such a case, the teaching operation must be performed while associating the rotation position or movement position of the work target with the tip position of the robot hand, which is very troublesome. However, it is technically difficult to start the rotation of the work target from the rotation position corresponding to the first teaching point during the playback operation. In addition, when performing position correction based on the taught position, it may not be possible to accurately position the working means such as the welding torch due to individual differences in the welding line or sealing line of the work target, and trace using the laser sensor. Even if the operation is performed, it is difficult to properly position the working means such as the welding torch by the usual means as long as there is an offset between the working means and the sensor.

An object of the present invention is to solve these drawbacks of the prior art and to provide a working means such as a welding torch even when performing work such as welding and sealing while giving movement such as rotation to a work target. An object of the present invention is to provide a real-time position correction method capable of performing position correction appropriately.

[0008]

According to the position correcting method of the present invention, the working means is fixed, the work object is moved, the offset direction of the laser sensor is set according to the moving direction of the work object, and the laser sensor is used. The measurement data of the laser sensor is stored until the measured position on the work target reaches the working unit, and the working unit is based on the measurement data when the position on the work target reaches the working unit. Alternatively, the above object was achieved by correcting the positional deviation of the work target.

[0009]

By setting the offset direction of the laser sensor according to the moving direction of the work object, the position measurement is executed in advance before the position on the work object reaches the working means and the measurement data is stored. Since the position deviation of the working means or the working object is corrected based on the measurement data when the position on the working object reaches the working means, a solid difference such as a welding line or a sealing line on the working object is corrected. Further, the positional deviation between the working means and the work target can be appropriately corrected regardless of the magnitude of the offset between the working means and the laser sensor.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram schematically showing an example of an industrial robot equipped with a welding device 3 and a laser sensor 4. The robot controller 1 that drives and controls the robot body 2 has a CPU 11, and the CPU 11 has a ROM 12 that stores control programs and the like, a RAM 16 that is used for temporary storage of data, and a non-volatile memory that stores various parameters and teaching data. 17, a teaching operation panel 13 for teaching motions to the robot, an operation panel 14, an axis controller 18 for driving and controlling each axis of the robot body 2 via a servo circuit 20, an input / output interface 19, and the like. Input / output interface 1 connected by bus 15.
The welding device 3 to which the above-described welding torch 31 is attached and the laser sensor 4 are connected to 9.

FIG. 2 is a conceptual diagram showing a setup state when a welding work is carried out by a welding torch 31 on a work target 5 in which a welding line 6 in the circumferential direction is defined on the outer peripheral portion of a cylinder, an annular ring or the like. Attached to an additional axis provided on the robot body 2 itself, another robot hand, or other rotation driving means capable of controlling the rotation speed, and at a predetermined rotation speed centered on the central axis α of the robot hand. It is designed to rotate in the direction. FIG. 2 exemplifies a case where the work target 5 is rotated by the rotation driving means having a control device capable of controlling the rotation speed and the rotation time. The control device of the rotation driving means is connected to the input / output interface 19 of the robot controller 1, receives the rotation start command from the robot controller 1 to start the rotation of the work target 5, and the rotation of the work target 5 is the predetermined rotation. When the speed is reached, a rotation start signal is output to the robot controller 1 via the input / output interface 19. Further, the control device of the rotation driving means receives the timer start command from the robot controller 1 to start measuring the rotation time, and when the predetermined rotation time corresponding to one rotation of the work target 5 has elapsed, the rotation driving means is driven. It stops and outputs a time-up signal to the robot controller 1.

The welding torch 31 is attached to the tip of the robot hand, and the welding device 3 having the welding torch 31 connected thereto is used.
Receives the welding start command from the robot controller 1 and starts the welding operation, while receiving the welding end command from the robot controller 1 and ends the welding operation. The tip of the robot hand further has a constant offset with respect to the central axis of the welding torch 31, and the laser sensor 4 disclosed in Japanese Patent Application No. 3-165038, Japanese Patent Application No. 3-240473, etc. Is mounted on the nonvolatile memory 17 so that the plane formed by the central axis of the welding torch 31 and the optical axis of the laser sensor 4 is substantially orthogonal to the central axis α of the work target 5, that is, the welding torch 31. The tip end position of the robot hand at the start of position measurement is taught in advance so that the offset direction of the laser sensor 4 with respect to the central axis of is the opposite direction to the rotational movement direction of the outer peripheral portion of the work target 5. When the work target 5 rotates as shown in FIG. 2, the offset direction of the laser sensor 4 with respect to the central axis of the welding torch 31 is opposite to the direction along the moving direction of the work target (example of FIG. 2). ) And vice versa, the method of the present invention can be applied (desirably, as shown in FIG. 2, the position on the work target 5 scanned by the laser sensor 4 is the welding torch 31). The rotation direction is set so that the distance to reach the work position is shortened, so it is better to offset in the direction opposite to the rotation movement direction.) When the work object moves linearly, the center of the welding torch 31 The offset direction of the laser sensor 4 with respect to the axis is limited to the side opposite to the moving direction of the work target. The scanning direction of the laser sensor 4 is the direction of the arrow β shown in FIG.
That is, it is the direction of the Y-axis orthogonal to the welding line 6 corresponding to the rotational movement direction of the work target 5, and the laser sensor 4 positions and shakes the laser reflected light imaged on the light receiving element for detecting the reflected light. Depending on the swing angle of the moving mirror, the distance between the laser sensor 4 and the welding line 6 on the work target 5 to be scanned (Z-axis direction in FIG. 2), as in the conventional case,
Also, the positional deviation of the welding line 6 with respect to the center of the sensor coordinate system (Y-axis direction in FIG. 2) is detected. The laser sensor 4 receives the measurement execution command from the robot controller 1 and detects the positional deviation data (y, z) of the welding line 6 at that time, and at the same time, outputs the data via the input / output interface 19. To CPU 11 in real time. As will be described later in detail, the output cycle of the measurement execution command, that is, the measurement execution interval of the laser sensor 4 is the set value ΔT.

As shown in FIG. 3, the offset amount of the laser sensor 4 with respect to the welding torch 31 is D, and
If the rotation speed (peripheral speed) of the work target 6 is V and the rotation direction is clockwise, the position P1 on the work target 5 scanned by the laser sensor 4 is the welding torch 31.
The time T required to reach the working position P2 of
In summary, T = D / V. In this embodiment, the measurement execution number integration counter n (one of the register of the RAM 16 or the general-purpose register of the CPU 11) that integrates the number of measurement executions of the laser sensor 4 is used as a time measuring means.
Position P1 on the work target 5 scanned by the laser sensor 4
Of the counter n corresponding to the time T required to reach the work position P2 of the welding torch 31, that is, the correction start timing determination value N, where N = T / ΔT is previously stored in the nonvolatile memory 17. It is stored as a parameter. Further, between the position P1 on the work target 5 scanned by the laser sensor 4 and the work position P2 of the welding torch 31, due to the curvature of the outer peripheral portion of the work target 5 formed of a cylinder or an annular ring,
A difference of ΔZ occurs in the distance direction (Z-axis direction in FIG. 3). Therefore, if the position correction of the welding torch 31 is attempted at the P2 point based on only the positional deviation data (y, z) measured at the P1 point, the problem that the welding torch 31 approaches the work target 5 more than necessary occurs. In order to avoid such a problem, in the non-volatile memory 17, the curvature and offset amount D of the work target 5 and the relative positional relationship between the work target 5 and the welding torch 31 (the central axis α of the work target 5 and the welding torch 31) are stored. The correction value ΔZ in the distance direction is stored in advance as a parameter in accordance with the degree of separation in the X-axis direction with respect to the center axis of the.

In the data storage area of the RAM 16,
Corresponding to the shift register-like file means A1 capable of cyclically shifting and storing N or more pieces of positional deviation data (y, z) input from the laser sensor 4 and the data (y, z). Further, there is provided a shift register-shaped file means A2 capable of cyclically storing N or more pieces of position / orientation data (X, Y, Z) of the robot hand at that point in time. FIG. 6 is a conceptual diagram schematically showing the configuration and function of the file means A1.
As shown in FIG. 6, the file means A1 has the positional deviation data (y1, which is first input from the laser sensor 4).
z1) is first stored in association with the storage area of address 1, and thereafter, every time new data is input, the data stored in the i-th address is sequentially shifted to the address of i + 1 and updated and stored. , Receives new data in the storage area of address 1. The configuration and function of the file means A2 that shift-stores the position / orientation data (X, Y, Z) of the robot hand and the like are also the same.

4 to 5 are flowcharts showing the outline of the "position correction process" performed by the CPU 11 of the robot controller 1 when the welding torch 31 performs welding work on the work target 5 consisting of a cylinder, an annular ring or the like. The processing operation of this embodiment will be described below with reference to FIGS. In addition, FIG.
The program corresponding to the processing shown in FIG. 5 is stored in advance in the ROM 12 as a part of the control program, but the correction start timing determination value N and the correction value ΔZ in the distance direction described above are stored.
The values such as are stored in the nonvolatile memory 17 as parameters in a nonvolatile manner, and the rewriting operation can be arbitrarily performed as necessary.

CPU 11 which has started the "position correction process"
First, the tip of the robot hand is moved to the positioning position at the time of starting the position measurement stored in advance in the non-volatile memory 17 (step S1), and the measurement execution number integration counter n,
Each of the correction process shift flag F1 and the welding process shift flag F2 is initialized (step S2), and then a rotation start command is output to the controller of the rotation driving means via the input / output interface 19 (step S3), and control is performed. A standby state waiting for a rotation start signal from the device is entered (step S
4). Upon receiving the rotation start command, the control device activates the rotation driving means to start the rotation of the work target 5 and detects that the rotation speed (peripheral speed) of the work target 5 has reached the preset rotation speed V. , And outputs a rotation start signal to the robot controller 1.

The CPU 11, which has detected the input of the rotation start signal in the determination processing of step S4, outputs a measurement execution command to the laser sensor 4 and outputs the position of the welding line 6 from the position on the work target 5 corresponding to the current scan area. Deviation data (x,
y) is detected and the current position and orientation data (X, Y, Z) of the robot hand is read (step S5), and each data is stored in the file means A1 of the RAM 16.
And are stored in A2 (step S6). As shown in the column of time 0 in FIG.
Positional deviation data (y1, z1) by the second measurement process
Is stored at address 1 of the file means A1, and
Position and orientation data of the robot hand (X
1, Y1, Z1) etc. will be stored at address 1 of the file means A2.

Next, the CPU 11 determines whether or not the correction process shift flag F1 is set (step S7), but at the present time point immediately after the start of measurement, the step S7 is performed.
Since the reset state of the flag F1 by the process of 2 is retained as it is, the determination result of step S7 is false. Therefore, the CPU 11 causes the measurement execution number integration counter n
Is incremented by 1 to store that the measurement process (the processes of steps S5 and S6) has been performed once (step S8), and the value of the counter n is the value of the correction start timing determination value N (hereinafter, It is determined whether or not the value has reached N (described as N = 3) (step S9). Since the value of the measurement execution number integration counter n is 1 at present, the determination result of step S9 is false, and the CPU 11 waits for a predetermined time (step S10), and then again returns to step S5.
The processing will shift to. The predetermined time here is a waiting time for making the processing for one loop from step S5 to step S10 coincide with the preset measurement execution period ΔT. In some cases, task management is used in which after the determination result in step S4 becomes true, the processing in step S5 and subsequent steps is repeatedly executed at predetermined intervals in synchronization with the clock cycle ΔT of the CPU 11, and in this case, step S10 is performed. The corresponding process is automatically executed as a process on hardware. Also, step S
In step 5, the timer for measuring the period ΔT is restarted, and in step S10 (the same applies to steps S12 and S20 described later), the timer waits until the timer expires, and the process proceeds to step S5. Good.

CPU 1 having moved to the processing of step S5
1 repeats the loop processing from step S5 to step S10 in the same manner as described above until the determination result of step S9 becomes true. In this example, the determination result of step S9 is true when the measurement process is 3
This is a stage where n = 3 has been executed once, and at this time, it was obtained by the third measurement process as shown in the column of time 2ΔT in the storage area of address 1 in the file means A1. The positional shift data (y3, z3) is stored, and the positional shift data (y2, z3) obtained by the second measurement process is stored in the storage area of the same address 2.
2) is shift-stored, and the displacement data (y1, z1) obtained by the first measurement process is shift-stored in the storage area of the same address 3. File means A
The same applies to 2.

Then, while repeatedly executing the loop-like processing from step S5 to step S10, step S
When the determination result of 9 becomes true, the "position correction process" of the next cycle is performed.
When it is detected that the N + 1th measurement process, that is, the fourth measurement process in this example, is about to be executed,
11 terminates the loop process described above, sets the correction process shift flag F1 (step S11), and executes the same standby process as described above (however, the standby time is different because the number of steps is different) (step S12). Then, the process proceeds to step S5 again, and the processes of step S5 and the next step S6 are executed in the same manner as described above.

The state of the file means A1 at this point is shown in FIG.
In the column of time 3ΔT (N + 1). File means A
The same applies to 2 as well.

CPU 11 which has completed the processing of step S6
Then determines whether or not the correction process shift flag F1 is set (step S7). Since the correction process shift flag F1 has already been set at this point, the determination result of step S7 is true. Although the value of the measurement execution number integration counter n at this time is held at the value of N, in the next processing cycle when the value of the measurement execution number integration counter n reaches N, that is, in the current processing cycle. Since new measurement processing has already been executed in the processing of steps S5 and S6, it means that N + 1 times of measurement processing has already been executed at this point.

Next, the CPU 11 causes the file means A1.
Address N + 1, that is, file means A in this example
Positional deviation data (yN +
1, zN + 1), and corresponding position / orientation data (XN + 1, YN + 1, ZN + 1) of the robot hand stored at the address N of the file means A2, and correction in the distance direction stored in the non-volatile memory 17. The value ΔZ is read, position correction data for the robot hand is created based on these values (step S13), the position correction data is output to the axis controller 18, and the tip position of the robot hand, that is, the welding torch 31 is output. The positional deviation is corrected so that the central axis is located on the welding line 6 of the work target 5 (step S14).

As is clear from the storage state of the positional deviation data shown in the column of time 3ΔT (N + 1) in FIG. 6, the data read from the file means A1 at this time is N processing cycles with respect to the processing cycle. Previously, that is, in this example, the measurement data before three processing cycles, and in any case, is the positional deviation data (y1, z1) in the first measurement processing. Then, the time at which the position shift data (y1, z1) is detected at the start of the "position correction process" is 0, and the Nth
The time at which the first misregistration correction process (the processes of step S13 and step S14) that is executed together with the + 1st measurement process is performed is NΔT, that is, 3ΔT in this example.
The value of NΔT is necessary until the position P1 on the work target 5 scanned by the laser sensor 4 when the work target 5 is rotated at the set speed V reaches the work position P2 of the welding torch 31. Corresponding to the required time T.

That is, in the first misregistration correction process, the work in which the predetermined rotational speed V is reached and the misregistration in the Y-axis and Z-axis directions is detected by the laser sensor 4 at point P1 at time 0 in FIG. The welding line 6 on the target 5 has a predetermined speed V
When the work position P2 of the welding torch 31, which is the working means, is reached after the lapse of time NΔT = T due to the rotation of the work target 5 rotating at, the positional deviation data before time NΔT = T,
That is, based on the positional deviation data measured by the laser sensor 4 at the point P1 at time 0, the position / orientation data of the robot hand at the time 0, and the correction value ΔZ in the distance direction, the present time at time NΔT = T. Welding torch 3
The positional deviation of 1 will be corrected.

The positional deviation correction processing in steps S13 and S14 is performed by the positional deviation of the welding line 6 on the work object 5 in which the positional deviation in the Y-axis and Z-axis directions with respect to the center of the sensor coordinate system is detected at the point P1. The data is converted into the amount of positional deviation of the robot coordinate system based on the position and orientation data of the robot hand at the time point P1, and the correction value ΔZ in the distance direction is subtracted from the Z-axis component to determine the target position for positioning the robot hand. Is calculated, and a deviation between the current position and orientation of the robot hand and the target position is calculated and output as correction data to the axis controller 18. Since the processing method itself regarding the coordinate conversion and the like is a mathematically well-known matter, its explanation is omitted.

The CPU 11 which has output the position correction data to the axis controller 18 then determines whether or not the welding process transition flag F2 is set (step S15).
At the current stage immediately after the first misregistration correction process is executed, the reset state of the flag F2 by the process of step S2 is held as it is, so step S15
The determination result of is false. Therefore, the CPU 11 outputs a welding start command to the welding device 3 via the input / output interface 19 to start the welding work by the welding device 3 (step S16), and also a control device of the rotation drive means for rotating the work target 5. To output a timer start command to the control device to start the rotation time measurement work by the control device (step S17), set the welding process shift flag F2 (step S18), and shift to the process of step S5 again. Becomes The time required to carry out the processes of steps S5 to S7 and steps S13 to S18 is ΔT.

In the next processing cycle, the processing of steps S5 to S7 and steps 13 to S15 is executed in the same manner as described above, and the newly detected positional deviation data (y, z) and the corresponding The position / orientation data (X, Y, Z) of the robot hand at the present time are sequentially shifted and stored in the file means A1 and A2 (step S5, step S6), and the address N + 1 of the file means A1 and A2 is stored at the present time. The positional deviation correction process is performed on the robot hand based on the positional deviation data stored in the area, the position / orientation data of the robot hand, and the correction value ΔZ in the distance direction described above (steps S13 and S14). . As a result of the measurement processing of steps S5 and S6 being synchronized with the positional deviation correction processing of steps S13 and S14, the data read from the file means A1 and A2 in step S13 is always in the processing cycle. On the other hand, the measured data is before N processing cycles, that is, before 3 processing cycles in this example. This is because the CPU 11 always
Position P1 on the work target 5 scanned by the laser sensor 4
Means that the position correction is performed based on the data before the required time T for reaching the work position P2 of the welding torch 31.

The CPU 11 that has output the position correction data to the axis controller 18 in the process of step S14 then determines whether or not the welding process transition flag F2 is set (step S15). Since the process shift flag F2 is set, the determination result of step S15 is true. Therefore, the CPU 11 determines whether or not the time-up signal is input from the control device of the rotation drive means (step S19). If the time-up signal is not input, the work target 5 after the welding work is started is judged. It means that the rotation has not reached one rotation, that is, the welding operation has not been completed. Therefore, step S
If the determination result of 19 is false, the CPU 11 executes the same standby process as that of steps S10 and S12 (however, the standby time is different because the number of steps is different) (step S20), and then the process of step S5 is performed again. In the same manner as described above, the process proceeds to the following steps until the input of the time-up signal from the control device of the rotation driving means is detected, in the same manner as described above.
Step S15 and steps S19 to S20
The above processing is repeatedly executed, and the above-described measurement processing and positional deviation correction processing are continuously executed in synchronization with each other.

While the above process is repeatedly executed, the input of the time-up signal from the controller of the rotation driving means is detected in the determination process of step S19, and the rotation of the work target 5 after the start of the welding work is detected. When it is confirmed that one rotation has been reached, the CPU 11 outputs a welding end signal to the welding device 3 to stop the operation of the welding torch 31 (step S21), and the series of "positions" shown in FIGS. The correction process ”is completed. Note that, as described above, the rotation driving means itself is automatically stopped by the processing of the control device which has finished measuring the predetermined time.

The degree of density of the measurement interval by the laser sensor 4 can be freely adjusted by changing the setting of the processing cycle ΔT. Further, since the measurement data is stored in advance, it is possible to perform the position correction in consideration of the response delay of the correction operation and the like. For example, Δ
If the delay of T occurs, the discrimination criterion in step S9 is set to "n≥N-1", and the read destination address in step S13 is set to "N".

As is clear from the above description, the position correcting operation of the robot hand by this "position correcting process" is substantially a copying control. Therefore, the operator need only teach the position data for carrying out the positioning (step S1) at the time of starting the measurement, and the welding torch 3
The operation is much simpler than the normal welding program creation process in which the robot hand equipped with 1 or the laser sensor 4 is moved and the position data is created by the teaching operation of a large number of points to perform the playback operation. This makes it possible to perform an appropriate welding work. In addition, if a robot hand is driven while rotating the work target 5 to perform welding work by using a method in which such a conventional teaching operation is extended, the rotation position of the work target 5 and the tip of the robot hand are used. Although it is very troublesome to perform the teaching operation for both of them while associating with the position, such teaching operation is not required at all in the present embodiment. Moreover, since the position P1 on the work target 5 scanned by the laser sensor 4 reaches the work position P2 of the welding torch 31, the position correction is performed based on the previous time T.
Regardless of the amount of offset between the welding torch 31 and the laser sensor 4, appropriate position correction can be performed in real time.

As an example, as described above, the file means A1 and A2 having a shift register-like function are used, and the position P1 on the work target 5 reaches the work position P2 of the welding torch 31 based on the data before the required time T. The example in which the position of the robot hand is corrected according to
A file means for storing all the positional deviation data (y, z) and position / orientation data (X, Y, Z) of the robot hand corresponding to the detection time and a timer means for measuring the current time are provided to correct the position. At the time of execution, the position correction data may be created by detecting the data whose difference from the current time is the required time T from the file means.

Further, in the above-described embodiment shown in FIGS. 1 to 6, when the work target 5 is rotated by using another robot hand or the like instead of the simple rotation driving means, the welding torch 31 and Instead of correcting the position of the robot hand on which the laser sensor 4 is attached, the work target 5
By correcting the position of the robot hand that rotates, the position correction equivalent to the above can be performed.

When position correction is performed on a work object that moves linearly, it is not necessary to set the correction value ΔZ in the distance direction, and the type of movement command changes from a rotation command to a linear feed command. The only difference is that the processing method shown in FIGS. 4 to 5 and the configuration of the file means shown in FIG. 6 can be applied as they are. In addition,
As described above, the offset direction of the laser sensor 4 is limited in the case of a work object that moves linearly.

Although not described in particular, the data of the diameter and the rotation speed (rpm) or rotation speed V (peripheral speed) of the work object 5 and the offset amount D are input from the operation panel 14 or the like to obtain the required time T. The automatic setting of the correction start timing determination value N and the automatic control of the rotation speed, the rotation time, etc. of the work target 5 by the robot controller 1 can be easily implemented according to the ordinary technical level.

[0037]

According to the real-time position correction method of the present invention, the offset direction of the laser sensor is set in accordance with the moving direction of the work object so that the position on the work object is measured in advance before reaching the work means. Is executed and the measured data is saved, and when the position on the work object reaches the work means, the position deviation of the work means or the work object is corrected based on the measured data. Even if the position is detected by the laser sensor while performing various processing, regardless of the individual difference such as the welding line or the sealing line on the work target and the magnitude of the offset between the working means and the laser sensor. Instead, it is possible to accurately correct the positional deviation between the working means and the work target.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing an example of an industrial robot equipped with a welding torch and a laser sensor.

FIG. 2 is a conceptual diagram showing an example of a set-up state when performing a welding work to which a method of the present invention is applied to a work target in which a circumferential welding line is defined on an outer peripheral portion such as a cylinder or an annulus.

FIG. 3 is a conceptual diagram showing an example of a relationship among a laser sensor, a welding torch (working means), and a work target.

FIG. 4 is a flowchart showing an outline of “position correction processing” in one embodiment.

FIG. 5 is a continuation of the flowchart showing the outline of the “position correction processing”.

FIG. 6 is a conceptual diagram showing a configuration and a function of a file unit used in “position correction processing”.

[Explanation of symbols]

 1 Robot Controller 2 Robot Main Body 3 Welding Device 4 Laser Sensor 5 Cylinder or Ring as Work Target 6 Welding Line 11 CPU 12 ROM 16 RAM 17 Nonvolatile Memory 18 Axis Controller 19 Input / Output Interface 31 Welding Torch D Offset Amount

Claims (3)

[Claims] 1. A laser sensor mounted with a constant offset amount with respect to a working means detects a relative positional relationship between the working object and the laser sensor and corrects a positional deviation between the working object and the working means. In the position correction method, the work object is moved, the offset direction of the laser sensor is set in accordance with the movement direction of the work object, and the position on the work object measured by the laser sensor until the work means is reached. A real-time position correction method in which the measurement data of the laser sensor is stored, and when the position on the work target reaches the working means, the positional deviation of the working means is corrected based on the measurement data. 2. A laser sensor attached to the working means with a certain offset amount detects a relative positional relationship between the working object and the laser sensor and corrects a positional deviation between the working object and the working means. In the position correction method, the working means is fixed, the work target is moved, the offset direction of the laser sensor is set in accordance with the movement direction of the work target, and the position on the work target measured by the laser sensor is the above-mentioned. The measurement data of the laser sensor is stored until the work means is reached, and when the position on the work object reaches the work means, the positional deviation of the work object is corrected based on the measurement data. Real-time position correction method. 3. The real-time position correction method according to claim 1, wherein the movement of the work target is rotational movement.