JP2000102869A - Welding robot with sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a welding robot with a laser sensor for surely detecting a work bent part even when a work is arranged at an approximate position. SOLUTION: A sensor 4 opposed to a work plane is moved in parallel to the taught estimated line KL, and the first sampling is performed at a given interval. Then, the sensor is dispositioned in a manner that the measured value of the sensor becomes a reference value. When the measured value at the time of the J-th sampling exceeds the first setting value, the sensor is moved by a given interval in an opposite direction to the first sampling, for performing the second sampling at a small interval in the same direction as the first sampling. When the sensor measured value at the time of the K-th sampling, or the K-th sensor measured value and the K-1st sensor measured value exceed a given setting value, a detected signal is output indicating that the bent part of the work plane is positioned between the K-1st and the K-th samplings.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for mounting a welding torch and a laser sensor at the tip of a robot arm and moving the sensor parallel to a taught line to detect a bent portion of a work plane. The present invention relates to a welding robot with a handle.

[0002]

2. Description of the Related Art Generally, in an arc welding robot, a microcomputer is operated based on input data from a teaching operation to operate the robot, thereby automatically performing welding. In this case, it is a major premise that the object to be welded is installed at a predetermined position during welding. However, in reality, the work to be welded is almost always displaced from the planned position. Therefore, the actual placement error of the work with respect to the planned position is grasped. The welding along the welding line is performed by correcting the position of the torch.

As shown in FIG. 9, when the workpieces W ₁₁ , W ₁₂ and the workpiece W ₂ are so-called fillet welded, for example, the workpiece W ₁₁ and the torch T have an angle α. It is arranged so that it becomes. Of course, be arranged such that the angle α is a weld object W ₁₂ and the torch T, paying attention to the torch T, torch T is large around the bent portion P of the welding subject W _11, W ₁₂ It needs to be turned. On the other hand, by utilizing the fact that the detectable range of the laser sensor is generally large, the laser sensor 4 attached to the tip of the robot arm is moved along the planned teaching line KL, and the actual position of the workpiece, particularly And the position of the bent portion P of the workpiece was detected.

[0004]

In the above-mentioned prior art, it is necessary to take care that the actual position of the workpiece is within the detectable range of the laser sensor with respect to the predetermined position of the workpiece. However, as shown in FIG. 10, if the actual mounting position of the object to be welded W ₁₁ is in the detectable range of the laser sensor 4 is mounted in the welded object W ₁₁ located outside the detectable range The position state could not be grasped, and of course, the position of the bent portion P of the workpiece to be located outside the detectable range could not be detected. Furthermore, in recent years, the length of the work to be welded tends to be long. Since it has to be performed, it takes a long time to handle the work to be welded. The present invention has been made in view of the above problems, and an object of the present invention is to provide a welding robot with a sensor that can reliably detect a bent portion of a work even when the work is arranged at a general position. .

[0005]

According to a first aspect of the present invention, a welding torch and a laser sensor are attached to a tip of a robot arm, and the sensor is arranged in parallel with a taught line. The present invention is applied to a welding robot with a sensor that detects a bent portion of a work plane by moving the same. The feature is that the sensor facing the work plane has a predetermined measurement range, and when the sensor is moved in parallel with the predetermined line, the first sampling is performed at predetermined intervals, The sensor is displaced so that the measured value of the sensor becomes a predetermined reference value at the time of sampling, and when the measured value of the sensor at each sampling is within the first set value, the measured value of the sensor becomes the predetermined reference value When the measured value of the sensor at the j-th sampling exceeds the first set value, or the measured value of the sensor at the j-th sampling and (j
-1) When the difference value from the measured value of the sensor at the time of the first sampling exceeds the second set value, the sensor is moved by a predetermined interval in a direction opposite to the first sampling, and thereafter,
The second sampling is performed in the same direction as the first sampling at intervals smaller than the first sampling, and when the measured value of the sensor at each sampling is within the third set value, the measured value of the sensor is The sensor is displaced so as to be the reference value, and when the measured value of the sensor at the k-th sampling exceeds the third set value, or the measured value of the sensor at the k-th sampling and (k
-1) When the difference from the sensor measured value at the time of the first sampling exceeds the fourth set value, the sampling (k−
1) To output a detection signal indicating that the bent portion of the work plane is located between the kth and the kth.

According to a second aspect of the present invention, a welding torch and a laser sensor are attached to a tip of a robot arm, and the sensor is moved in parallel with a predetermined taught line to detect a bent portion of a work plane. Applied to welding robots. The feature is that the sensor facing the work plane has a predetermined measurement range, and when the sensor is moved in parallel with the predetermined line, the first sampling is performed at predetermined intervals, The sensor is displaced so that the measured value of the sensor becomes a predetermined reference value at the time of sampling, and when the measured value of the sensor at each sampling is within the first set value, the measured value of the sensor becomes the predetermined reference value When the measured value of the sensor at the j-th sampling exceeds the first set value, or the measured value of the sensor at the j-th sampling and (j
-1) When the difference value from the measured value of the sensor at the time of the first sampling exceeds the second set value, the sensor is moved by a predetermined interval in a direction opposite to the first sampling, and thereafter,
The second sampling is performed in the same direction as the first sampling at intervals smaller than the first sampling, and when the measured value of the sensor at each sampling is within the third set value, the measured value of the sensor is The sensor is displaced so as to be the reference value, and when the measured value of the sensor at the k-th sampling exceeds the third set value, or the measured value of the sensor at the k-th sampling and (k
-1) When the difference from the sensor measured value at the time of the first sampling exceeds the fourth set value, the sampling (k−
1) outputting a first detection signal indicating that the first bent portion of the work plane is located between the k-th and the k-th positions, and thereafter, near the reference sampling position in the direction opposite to the first sampling; The sensor is moved, and then a third sampling is performed at a predetermined interval in a direction opposite to the first sampling,
When the measured value of the sensor at each sampling is within the first set value, the sensor is displaced such that the measured value of the sensor becomes the reference value, and the measured value of the sensor at the m-th sampling is the first value. When the set value is exceeded, or the measured value of the sensor at the m-th sampling and (m
-1) When the difference value from the measured value of the sensor at the time of the first sampling exceeds the second set value, the sensor is moved by a predetermined interval in a direction opposite to that of the third sampling, and thereafter,
The fourth sampling is performed at intervals smaller than the third interval in the same direction as the third sampling, and when the measured value of the sensor at each sampling is within the third set value, the measured value of the sensor is The sensor is displaced so as to be the reference value, and when the measured value of the sensor at the time of the n-th sampling exceeds the third set value, or the measured value of the sensor at the time of the n-th sampling, and (n
-1) When the difference value from the measured value of the sensor at the time of the first sampling exceeds the fourth set value, (n-
1) To output a second detection signal indicating that the second bent portion of the work plane is located between the nth and the nth.

According to a third aspect of the present invention, a welding torch and a laser sensor are attached to the end of a robot arm, and the sensor is moved in parallel with a taught predetermined line to detect a bent portion of a work plane. Applied to welding robots. The feature is that the sensor facing the work plane has a predetermined measurement range, and when the sensor is moved in parallel with the predetermined line, the first sampling is performed at predetermined intervals, The sensor is displaced so that the measured value of the sensor becomes a predetermined reference value at the time of sampling, and when the measured value of the sensor at each sampling is within the first set value, the measured value of the sensor becomes the predetermined reference value When the measured value of the sensor at the j-th sampling exceeds the first set value, or the measured value of the sensor at the j-th sampling and (j
-1) When the difference value from the measured value of the sensor at the time of the first sampling exceeds the second set value, the sensor is moved by a predetermined interval in a direction opposite to the first sampling, and thereafter,
The second sampling is performed in the same direction as the first sampling at intervals smaller than the first sampling, and when the measured value of the sensor at each sampling is within the third set value, the measured value of the sensor is The sensor is displaced so as to be the reference value, and when the measured value of the sensor at the k-th sampling exceeds the third set value, or the measured value of the sensor at the k-th sampling and (k
-1) When the difference from the sensor measured value at the time of the first sampling exceeds the fourth set value, the sampling (k−
1) outputting a first detection signal indicating that the first bent portion of the work plane is located between the k-th and the k-th positions, and thereafter, near the reference sampling position in the direction opposite to the first sampling; The sensor is moved, and then the sensor performs the third sampling along the predetermined line in the direction opposite to the second sampling at the same interval as the second sampling. When the measured value is within the third set value, the sensor is displaced so that the measured value of the sensor becomes the reference value, and the measured value of the sensor at the time of the n-th sampling exceeds the third set value. Or the measured value of the sensor at the time of the n-th sampling, and (n
-1) When the difference value from the measured value of the sensor at the time of the first sampling exceeds the fourth set value, (n-
1) To output a second detection signal indicating that the second bent portion of the work plane is located between the nth and the nth.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. In FIG. 1, 1 is a robot controller, 2 is a sensor controller, 3 is a robot body,
Reference numeral 4 denotes a laser sensor, and reference numeral 5 denotes a welding torch. FIG.
Output characteristic diagram and FIG. 3 of the laser sensor 4 is a graph showing a measurement relationship between the work position of the laser sensor 4 based on the output characteristic diagram of FIG. 2, for example, a position distant from the laser sensor 4 by a predetermined distance L ₀ A zero voltage is output when the work is located at the position L, and a negative voltage −Va is output when the work is located at the laser sensor 4 side by ΔL than the distance L ₀ , while the work is at a distance from the distance L ₀ . Also, a positive voltage Va is output when the laser sensor 4 is located away from the laser sensor 4 by ΔL, and the range between the voltage Va and −Va is used as a measurement range of the laser sensor 4.

Although the voltages Va to -Va are output depending on the position of the work with respect to the laser sensor 4, the position of the work and the output voltage are maintained in a direct proportional relationship. When the work is located outside the measurement range with respect to the laser sensor 4, that is, when the distance from the laser sensor 4 to the work is L, and L> L ₀ + ΔL and L <L ₀ −ΔL, the voltage is A voltage Vmax larger than the absolute value of Va is output from the laser sensor 4 to the sensor controller 2. That is, as shown in FIG. 3, L ₀ −ΔL ≦ L
When the work is located at a position where ≦ L ₀ + ΔL is within the measurement range of the laser sensor 4, a measured voltage −Va ≦ V ≦ Va corresponding to the position of the work is output.

By the way, the width and length of the work in question is different, for example, as shown in FIG. 4, X ₂ direction of the end portion of the workpiece schematically as becomes a range M ₀ While being placed, X ₁ direction of the end portion of the workpiece position by the kind of work has become possible varies. Further, it is assumed that the end of the Y ₂ direction of the workpiece are also arranged in the schematic positions. The sampling start position of the laser sensor 4 is
Position the workpiece is present to ensure the X ₂ direction, is set at a position, for example X _K1. Further, as described above, a zero voltage is assumed to be output when the workpiece away from the laser sensor 4 by a predetermined distance L ₀ position is located.

[0011] As shown in FIG. 5, for example, a robot body 3 is actuated, when the laser sensor 4 is arranged such that the position of the X _K1 on the predetermined line KL, the position of the plane of the work schedule have shifted by y1 in Y ₁ direction from the position, the shift amount y1 is assumed to be smaller than the measurement range amount ΔL of the positive side of the laser sensor 4. In this case, an output voltage corresponding to the displacement amount y1 is output from the laser sensor 4 to the sensor controller 2, and the robot controller 1 appropriately operates the robot body 3 so that the output voltage becomes zero. That is, the laser sensor 4
Is located at the position of X _K1 on the scheduled line KL. At the time of the first reference sampling, the laser sensor 4 is positioned so that the measured value of the laser sensor 4 becomes a predetermined reference value, for example, the output voltage becomes zero. Displaced. In the above case, the laser sensor 4 is y1 only positional displacement in the Y ₁ direction relative scheduled line KL. Thereafter, the laser sensor 4 is moved in parallel with the predetermined line KL.
_After moving in _one direction, the second and subsequent samplings are performed at intervals of, for example, t1.

In order to detect the work position in the second and subsequent samplings, a target detection range of the laser sensor 4, that is, a first set value ± ΔL _S1 is set in advance. As shown in FIG. 6, the first set value ± ΔL _S1 is based on the sampling interval t1 and the work arrangement detection angle ± γ with respect to a line parallel to the planned work line WL.
Are set relatively. Note that the first set value ± ΔL
_S1 can be set to the measurement range ± ΔL of the laser sensor 4 itself, but it is preferable that the absolute value of ΔL _S1 is selected to be smaller than the absolute value of ΔL for reliable detection and control. After the 1st sampling, the laser sensor 4 is moved in the X ₁ direction going line KL parallel spaced t1, the second sampling is performed. In this case, parallel to the planned lines WL of the workpiece, if the relative scheduled lines WL ₁ spaced in the Y ₁ direction by a distance y1, the position of the plane of the workpiece are shifted by y2 in Y ₁ direction, the deviation An output voltage corresponding to the quantity y2 is detected. When the detected value corresponding to y2 is smaller than the value corresponding to the first set value ΔL _S1 , the measured value of the laser sensor 4 becomes a predetermined reference value, for example, the output voltage becomes zero as described above. so that the laser sensor 4 is positioned displaced y2 in Y ₁ direction. Thereafter, the laser sensor 4 is moved only X ₁ direction going line KL parallel spaced t1, sampling after the third is performed repeatedly. Incidentally, the second, third, ... Y ₁ direction deviation amount y2, y of the workpiece
3,... Have some variations due to the undulation of the work surface, etc., but since the work plane is almost straight, the second and third
Th amount of deviation Y ₁ direction ... becomes each approximate to y2 values.

[0013] In FIG. 5, when the (j-1) -th sampling, the detected value of the laser sensor 4, i.e., the detection voltage corresponding to the work plane Y ₁ direction shift amount y (j-1) is first When the measured value of the laser sensor 4 is smaller than the value corresponding to the set value ΔL _S1 of, for example,
Output voltage as described above so that the zero, the laser sensor 4 is positioned displaced in Y ₁ direction by y (j-1) ≒ y2 .

Further, the (j-1) -th and j-th
Bending part P of work plane between samplings ₁Where there is
In the case of the j-th sampling,
Since there is no work within the measurement range, the laser sensor 4
Outputs a detection voltage Vmax. This detection voltage Vmax
Is the first set value ΔL_S1Greater than the value corresponding to
Therefore, sampling by the laser sensor 4 is stopped.
It is. The process up to this point is the first sampling.
You.

[0015] Thereafter, in parallel with the laser sensor 4 and scheduled line KL than stop point it is moved by a suitable distance in the X ₂ direction.
For example, the laser sensor 4 is moved to the (j-1) th position. This position is set as the second sampling start position, and the second sampling is performed in the same manner as the first sampling at an interval of t2 shorter than the first sampling interval t1. Of course, in this case, the first set value ± ΔL _S1 shown in FIG.
L _S3 is relatively set by the sampling interval t2 and the work arrangement detection angle ± γ, and the third set value ± ΔL _S3 is selected to be smaller than the first set value ± ΔL _S1. You. In the second sampling, the (k
-1) th time of sampling, the detection value of the laser sensor 4, i.e., the work plane Y ₁ direction shift amount y (k-
When the detected voltage corresponding to 1) is smaller than the value corresponding to the third set value ± ΔL _S3 , the laser sensor 4
Measurements, for example, so that the output voltage as described above is zero, the laser sensor 4 is positioned displaced by y (k-1) to Y ₁ direction.

Further, when the detection voltage Vmax is output from the laser sensor 4 at the time of the k-th sampling, no work exists within the measurement range of the laser sensor 4, so that the (k-1) -th and the (k-1) -th it is determined the presence of bent portion P ₁ of the work plane between the k-th.

That is, the bent portion P ₁ of the work is roughly detected by the first sampling, and the accurate position of the bent portion P ₁ of the work is detected by the second sampling. Bend P on one side of the work plane
_{The first} method for detecting 1 is procedure 1.

[0018] Next, a second method for detecting a bent portion P ₁ on one side of different shapes of the work plane as Step 2. Figure 7 is a diagram showing a case bent portion P ₁ of the work plane is obtuse, the first sampling in analogy to the method described above step 1 is performed. In the above, between the (j-1) -th and j-th samplings, the bent portion P of the work plane
It is assumed _{that 1} is present.

Now, in the first sampling similar to the method of the above procedure 1, the detection value of the laser sensor 4 at the time of the second sampling, that is, Y _{1 of} the work plane.
The detected voltage corresponding to the direction deviation amount y2 is the first set value Δ
When the L _S1 is smaller than the corresponding values are measured values of the laser sensor 4, for example, so that the output voltage as described above is zero, the laser sensor 4 in the Y ₁ direction y2
Is only displaced. Incidentally, since the work plane as described above is almost a straight line, the third, fourth, displacement of Y ₁ direction ... becomes each approximate to y2 values. Therefore, if when bent portion P ₁ of the work plane and are not present in the first through j th between, (j-1) th th and Y ₁ direction of the work plane during the j-th sampling Are the values y (j-1) and yj of which are approximate to y2, respectively.

However, as shown in FIG.
1) th and if the bent portion P ₁ of the work plane is present between the j-th sampling, a value corresponding to the j-th workpiece plane during sampling Y ₁ direction shift amount Δy is the output Is done. In this case, if the value corresponding to Δy is,
Even if the value is smaller than the value corresponding to the first set value ΔL _S1 , the difference between the measured value of the sensor at the j-th sampling and the measured value of the sensor at the (j−1) -th sampling is obtained. When the value exceeds a preset value related to the work plane, that is, the second set value ΔL _S2 , the bent portion P of the work plane is interposed between the (j−1) -th and j-th samplings.
_Assuming that ₁ exists, sampling by the laser sensor 4 is stopped. That is, the second set value ΔL _{S2, which} is a judgment value of a difference value between the sensor measurement value at the j-th sampling and the sensor measurement value at the (j−1) -th sampling, is the work plane state. Is set appropriately in consideration of

[0021] Thereafter, it is moved by appropriate intervals scheduled line KL parallel to the laser sensor 4 than the stop point in the X ₂ direction,
The second sampling is performed in the same manner as in the procedure 1 above. That is, at the interval t2 shorter than the first sampling interval t1, the second sampling is performed in the same manner as in the first sampling. In this case, the third set value ± ΔL as described above is used for the second sampling.
_S3 is set. In the second sampling, the third set value ± ΔL _S3 is smaller than the first set value ± ΔL _S1 , but the measured value of the sensor at the j-th sampling and the (j−1) As the fourth set value ΔL _{S4, which} is a judgment value of a difference value from the sensor measured value at the time of the first sampling, a value smaller than the second set value ΔL _S2 for the first sampling is selected. In the second sampling, the difference between the sensor measured value at the k-th sampling and the sensor measured value at the (k-1) -th sampling exceeds the fourth set value ΔL _S4 . When the (k-
1) th and it is determined that the presence of the bent portion P ₁ of the work plane is between the k-th sampling.

[0022] As described above, steps 1 or after detecting the bent portion P ₁ on one side of the workpiece plane by Step 2, Step 3 the third method of detecting a bent portion P ₂ of the other side of the work plane It will be described as. 8, after the above step 1 or step 2, a diagram related to the trajectory of the laser sensor 4 in the case of detecting a bent portion P ₂ of X ₂ direction side of the work plane, X ₁ of the work plane as described above after detecting the bent portion P ₁ of the direction, the laser sensor 4 is the first sampling start position, i.e. such that the reference sampling location X _k1 near the laser sensor 4 is moved in the X ₂ direction. Incidentally, as shown in FIG. 5, in a state where the bent portion P ₁ of the X ₁ side of the workpiece plane is detected, the position of the laser sensor 4 is substantially the planned line KL in Y ₁ direction distance y2 *
The position is displaced by (j-2). Therefore, for example, when the laser sensor 4 is moved to the position X _k1 , the laser sensor 4 is displaced in the Y ₂ direction by the interval y2 * (j−2).

[0023] As described above, the laser sensor 4 is selected at an appropriate position in the Y ₂ direction, and the position and the sampling start position, by the laser sensor 4 is moved in parallel with the scheduled line KL, th 1st sampling the reverse direction, i.e. X in the _two directions at predetermined intervals the third round of sampling is performed. In this case, for example, the sampling interval t
1 and the first set value ± ΔL _S1 and the second set value Δ
L _S2 is selected in the same manner as in the procedure 1 and the procedure 2, and is performed in the same manner as the first sampling in the procedure 1.

[0024] Now, between the (m-1) th and m-th, it is assumed that the bent portion P ₂ of X ₂ direction side of the workpiece plane is present. In this case, the (m-1) th to the time of sampling, each position of the plane of the workpiece is substantially the Y ₂ direction y
2 and the detected value corresponding to y2 is the first value.
Is smaller than the value corresponding to the set value ΔL _S1 , the measured value of the laser sensor 4 is a predetermined reference value, for example,
Output voltage as described above so that the zero, the laser sensor 4 is positioned displaced by substantially y2 in Y ₂ direction.

[0025] After the (m-1) th sampling, the laser sensor 4 is moved in the X ₂ direction going line KL parallel spaced t1, the m-th sampling is carried out.
In this case, the state is one of the two cases. First case; when the work plane is shifted significantly to the Y ₁ direction, the detection voltage Vmax is output from the laser sensor 4. Since this detection voltage Vmax is a value larger than the value corresponding to the first set value ΔL _S1 , the laser sensor 4
Is stopped. Second case; when the deviation amount in the Y ₁ direction of the work plane is not so large, the work plane at the time of sampling Y ₁
A value corresponding to the direction deviation amount Δy is output. Of course, until the (m-1) th sampling, whereas the negative measuring voltage for displacement of the work plane is Y ₂ direction is outputted, at the time of the m-th sampling, Y ₁ direction deviation A positive measurement voltage corresponding to the quantity Δy is output. In this case, even if the value corresponding to Δy is smaller than the value corresponding to the first set value ΔL _S1 , the measured value of the sensor at the m-th sampling and the (m−1)
When the difference from the sensor measurement value at the time of the second sampling exceeds the second set value ΔL _S2 , the bent portion of the work plane is interposed between the (m−1) th and mth samplings. P
_Assuming that ₂ exists, sampling by the laser sensor 4 is stopped.

Thereafter, the recording is performed from the stop point in parallel with the predetermined line KL.
User sensor 4 is X₁It is moved in the direction by an appropriate interval.
For example, a laser sensor up to the (m-1) th position
4 is moved. Open this position for the fourth sampling
The start position, which is shorter than the third sampling interval t1
At intervals of t2, the fourth session is performed in the same manner as the third session.
Sampling is performed. Of course, the fourth sun pudding
The sampling interval t2 is longer than the third sampling interval t1.
Since the selection is made short, the
Set value of 3 ± ΔL _S3Is the first set value ± ΔL_S1Smaller than
And the fourth set value ± ΔL_S4Also the second
Set value ± ΔL_S2Is chosen to be smaller than In addition,
At the time of the fourth sampling, the (n-1) th and
Bend P of the work plane during the nth sampling_TwoBut
Assume it exists. In this case, up to the (m-1) th
At the time of sampling, Y_TwoMisalignment of direction
The amount is the third set value ± ΔL_S3Less than the value corresponding to
Value, the measured value of the laser sensor 4 is
Value, for example, as described above, so that the output voltage is zero.
And the laser sensor 4 is Y_TwoIs displaced in the direction.

[0027] After the (m-1) th sampling, the laser sensor 4 is moved in the X ₂ direction going line KL parallel spaced t2, the m-th sampling is carried out.
In this case, the detection voltage Vmax from the laser sensor 4 becomes the third voltage.
If the value is larger than the value corresponding to the set value ΔL _S3 , the sampling by the laser sensor 4 is stopped. Alternatively, even if the value corresponding to the displacement amount Δy in the Y direction of the work plane detected at the time of sampling is smaller than the value corresponding to the third set value ΔL _S3 ,
The measured value of the sensor at the time of the
When the difference value between the measured value of the sensor at 1) -th sampling, beyond the fourth set value ± [Delta] L _S4, the (m-
As bent portion P ₂ of the work plane is present between 1) th and m-th sampling, sampling by the laser sensor 4 is stopped. It is determined the presence of bent portions P ₂ of the work plane between the (m-1) th and m-th the above.

As described above, after detecting the bent portion of the work plane by the procedure 1 or the procedure 2, the third time and the fourth time
Procedure 3 is a third method for detecting the bent portion on the other side of the work plane by the second sampling.

[0029] In the step 3, omitted the third round of sampling, by the fourth round of sampling, the fourth method for detecting a bent portion P ₂ of the other side of the workpiece plane as Step 4 be able to. In this case, sampling is performed at a fine interval t2 in a state where the laser sensor 4 is appropriately positioned so as to be near the first sampling start position, that is, near the reference sampling position X _k1 .

According to the above procedures 1 to 3, since the bent portion of the work is roughly detected at a wide interval by the first sampling, even if the interval from the sampling start position to the bent portion of the work is long, The bent portion of the work can be roughly detected in a relatively short time, and the accurate position of the bent portion of the work can be reliably detected by the subsequent sampling at minute intervals.

Further, according to the above procedure 4, the 4th corresponding sampling start position is a position near a work in the X direction exists surely, until the bent portion P ₂ of the workpiece from the start position Is relatively short, the accurate position of the bent portion of the work can be reliably detected in a relatively short sampling time even when sampling at a fine interval.

In the above-mentioned sampling, the shift amount of the position of the work plane with respect to the scheduled line KL of the laser sensor 4 is taken into an appropriate storage device for each sampling, and the plane state of the work is grasped from the stored data. At the time of actual welding work, teaching data previously taught to the robot can be appropriately corrected.

Of course, at the time of the first reference sampling, the laser sensor 4 is arranged at a predetermined position on the scheduled line KL, for example, at the position of X _K1.
Is separated from the work by a preset installation error amount of the work with respect to the scheduled line KL, and the first sampling can be performed.

[0034]

As apparent from the above description, the first embodiment
The welding robot with a sensor according to the invention of the present invention, a welding torch and a laser sensor attached to the tip of the robot arm,
In a welding robot with a sensor for detecting the bent portion of the work plane by moving the sensor in parallel with the taught scheduled line, the sensor facing the work plane has a predetermined measurement range, and When moving in parallel with the predetermined line, the first sampling is performed at a predetermined interval, and the sensor is displaced so that the measured value of the sensor becomes the predetermined reference value at the time of reference sampling. When the measured value is within the first set value, the sensor is displaced so that the measured value of the sensor becomes a predetermined reference value, and the measured value of the sensor at the j-th sampling exceeds the first set value. Or the measured value of the sensor at the j-th sampling, and (j
-1) When the difference value from the measured value of the sensor at the time of the first sampling exceeds the second set value, the sensor is moved by a predetermined interval in a direction opposite to the first sampling, and thereafter,
The second sampling is performed in the same direction as the first sampling at intervals smaller than the first sampling, and when the measured value of the sensor at each sampling is within the third set value, the measured value of the sensor is The sensor is displaced so as to be the reference value, and when the measured value of the sensor at the k-th sampling exceeds the third set value, or the measured value of the sensor at the k-th sampling and (k
-1) When the difference from the sensor measured value at the time of the first sampling exceeds the fourth set value, the sampling (k−
1) In order to output a detection signal indicating that the bent portion on one side of the work plane is located between the 1st and kth positions, the bent portion of the work is roughly detected at a wide interval by the first sampling, Even if the distance from the sampling start position to the bent part on one side of the work is long, the bent part of the work can be roughly detected in a relatively short time. , The accurate position of the bent portion on one side of the work is reliably detected.

Further, the welding robot with a sensor according to the second aspect of the present invention, in addition to the first aspect of the present invention, further comprises the first robot from the vicinity of the reference sampling position toward the bent portion on the other end side of the workpiece. A third substantially identical to the second and the second
Since the fourth and fourth samplings are performed, the exact positions of the bent portions on both sides of the work are reliably detected.

Further, in the welding robot with the sensor according to the third aspect of the present invention, in addition to the first aspect of the present invention, the welding robot further includes a fine second portion extending from the vicinity of the reference sampling position toward the bent portion on the other end side of the workpiece. Since sampling is performed for the second time, accurate positions of the bent portions on both sides of the work are reliably detected.
Of course, the sampling start position corresponding to the second time is X
Since the distance from the start position to the bent portion of the work is relatively short near the position where the work reliably exists in the direction, the work of the work can be performed with a relatively short sampling time even if a minute interval is sampled. The accurate position of the bent portion on the other end is reliably detected.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is an output characteristic diagram of the laser sensor used in FIG.

FIG. 3 is a view showing a measurement relationship of a work position by a laser sensor used in FIG. 1;

FIG. 4 is an explanatory view of an arrangement state of a work in FIG. 1;

FIG. 5 is an explanatory diagram of a sampling state in FIG. 1;

FIG. 6 is an enlarged explanatory view of a main part in FIG. 5;

FIG. 7 is an enlarged explanatory diagram of a sampling state at a bent portion of a work end in FIG. 5;

FIG. 8 corresponds to FIG. 5 and illustrates a sampling state of a bent portion on both sides of a work.

FIG. 9 is a perspective view for explaining a conventional example.

FIG. 10 is a diagram for explaining a conventional example.

[Explanation of symbols]

1 ... robot controller 2 ... sensor controller 3 ... robot body 4 ... laser sensor 5 ... welding torch KL ... planned placement line teaching preset lines WL ... work of the laser sensor 4 [Delta] L _S1 ... first set value [Delta] L _S2 ... second Set value ΔL _S3 ... third set value ΔL _S4 ... fourth set value

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masanari Fujita 2-1-1, Tagawa, Yodogawa-ku, Osaka-shi Daihen Co., Ltd. F-term (reference) 5F072 MM12 YY06

Claims (3)

[Claims] 1. A welding robot with a sensor, wherein a welding torch and a laser sensor are attached to a tip of a robot arm, and the sensor is moved in parallel with a taught predetermined line to detect a bent portion of a work plane. The sensor facing the work plane has a predetermined measurement range, and performs a first sampling at a predetermined interval when moving the sensor in parallel with the predetermined line. When the measured value of the sensor at the time of each sampling is within the first set value, the sensor is displaced so that the measured value of the sensor becomes the predetermined reference value. The measured value of the sensor at the j-th sampling exceeds the first set value, or the measured value of the sensor at the j-th sampling and (j
-1) When the difference value from the sensor measured value at the time of the first sampling exceeds the second set value, the sensor is moved by a predetermined interval in a direction opposite to the first sampling, and thereafter, the first The second sampling is performed in the same direction as the first sampling at intervals smaller than the first interval, and when the measured value of the sensor at each sampling is within the third set value, the measured value of the sensor is equal to the reference value. When the measured value of the sensor at the k-th sampling exceeds the third set value, or the measured value of the sensor at the k-th sampling and (k
-1) When the difference from the sensor measured value at the time of the first sampling exceeds the fourth set value, the sampling (k−
1) A welding robot with a sensor that outputs a detection signal indicating that a bent portion of a work plane is located between the kth and kth positions. 2. A welding robot with a sensor, wherein a welding torch and a laser sensor are attached to a tip of a robot arm, and the sensor is moved in parallel with a taught predetermined line to detect a bent portion of a work plane. The sensor facing the work plane has a predetermined measurement range, and performs a first sampling at a predetermined interval when moving the sensor in parallel with the predetermined line. When the measured value of the sensor at the time of each sampling is within the first set value, the sensor is displaced so that the measured value of the sensor becomes the predetermined reference value. The measured value of the sensor at the j-th sampling exceeds the first set value, or the measured value of the sensor at the j-th sampling and (j
-1) When the difference value from the sensor measured value at the time of the first sampling exceeds the second set value, the sensor is moved by a predetermined interval in a direction opposite to the first sampling, and thereafter, the first The second sampling is performed in the same direction as the first sampling at intervals smaller than the first interval, and when the measured value of the sensor at each sampling is within the third set value, the measured value of the sensor is equal to the reference value. When the measured value of the sensor at the k-th sampling exceeds the third set value, or the measured value of the sensor at the k-th sampling and (k
-1) When the difference from the sensor measured value at the time of the first sampling exceeds the fourth set value, the sampling (k−
1) outputting a first detection signal indicating that the first bent portion of the work plane is located between the k-th position and the k-th position, and thereafter, near the reference sampling position in the direction opposite to the first sampling; The sensor is moved. Next, a third sampling is performed at a predetermined interval in a direction opposite to the first sampling, and when the measured value of the sensor at each sampling is within the first set value, the measurement of the sensor is performed. Displacing the sensor so that the value becomes the reference value, when the measured value of the sensor at the m-th sampling exceeds the first set value, or the measured value of the sensor at the m-th sampling, (M
-1) When the difference value from the measured value of the sensor at the time of the first sampling exceeds the second set value, the sensor is moved by a predetermined interval in a direction opposite to the third sampling, and thereafter, the third The fourth sampling is performed in the same direction as the third sampling at intervals smaller than the third interval, and when the measured value of the sensor at each sampling is within the third set value, the measured value of the sensor is equal to the reference value. When the measured value of the sensor at the n-th sampling exceeds the third set value, or the measured value of the sensor at the n-th sampling, and (n
-1) When the difference value from the measured value of the sensor at the time of the first sampling exceeds the fourth set value, (n-
1) A welding robot with a sensor that outputs a second detection signal indicating that the second bent portion of the work plane is located between the nth and the nth. 3. A welding robot with a sensor, wherein a welding torch and a laser sensor are attached to a tip of a robot arm, and the sensor is moved in parallel with a taught predetermined line to detect a bent portion of a work plane. The sensor facing the work plane has a predetermined measurement range, and performs a first sampling at a predetermined interval when moving the sensor in parallel with the predetermined line. When the measured value of the sensor at the time of each sampling is within the first set value, the sensor is displaced so that the measured value of the sensor becomes the predetermined reference value. The measured value of the sensor at the j-th sampling exceeds the first set value, or the measured value of the sensor at the j-th sampling and (j
-1) When the difference value from the sensor measured value at the time of the first sampling exceeds the second set value, the sensor is moved by a predetermined interval in a direction opposite to the first sampling, and thereafter, the first The second sampling is performed in the same direction as the first sampling at intervals smaller than the first interval, and when the measured value of the sensor at each sampling is within the third set value, the measured value of the sensor is equal to the reference value. When the measured value of the sensor at the k-th sampling exceeds the third set value, or the measured value of the sensor at the k-th sampling and (k
-1) When the difference from the sensor measured value at the time of the first sampling exceeds the fourth set value, the sampling (k−
1) outputting a first detection signal indicating that the first bent portion of the work plane is located between the k-th position and the k-th position, and thereafter, near the reference sampling position in the direction opposite to the first sampling; The sensor is moved, and then the sensor is subjected to a third sampling along the predetermined line in the direction opposite to the second sampling at the same interval as the second sampling. When the measured value is within the third set value, the sensor is displaced so that the measured value of the sensor becomes the reference value, and the measured value of the sensor at the time of the n-th sampling exceeds the third set value. Or the measured value of the sensor at the time of the n-th sampling, and (n
-1) When the difference value from the measured value of the sensor at the time of the first sampling exceeds the fourth set value, (n-
1) A welding robot with a sensor that outputs a second detection signal indicating that the second bent portion of the work plane is located between the nth and the nth.