JP3016328B2 - Measurement area correction device in measurement equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring area correcting device in a measuring apparatus, and more particularly to a measuring area correcting apparatus which automatically follows a deviation of a work in a lot.

[0002]

2. Description of the Related Art Recently, non-contact type measuring devices utilizing laser light or the like have become widespread, and are used in various fields. FIG. 4 shows an example of a panel measuring device for measuring the shape of a panel component of an automobile, for example. The panel measurement device 1 includes a measurement device main body 3 on which a measurement sensor 2 is attached, a measurement controller 4 for controlling the measurement device main body 3 including the measurement sensor 2, and measurement data for statistically processing a measurement result of the measurement sensor 2. And a statistical processing device 5. The measurement sensor 2 has, for example, a laser light source 6 and a detector (such as a light receiving element) 7 as shown in FIG. 5, and is attached to a wrist 8 of the robot. In this case, the laser light emitted from the laser light source 6 of the measurement sensor 2 is reflected on the surface of the panel component 9 and received by the detector 7 of the measurement sensor 2.

The measurement area M of the panel measurement device 1 is determined by the movable range of the measurement sensor 2 attached to the robot, in other words, by the irradiation range of the laser beam (see FIG. 6A). In panel measurement, etc., the displacement of the work in the lot becomes large and the measurement area M
If it deviates to some extent, it will not be possible to measure. For example, as shown in FIG. 6A, if the panel component 9 serving as a work exists at the position P in the measurement area M, the measurement point sequence data at that time can be obtained as shown in the upper diagram of FIG. The feature point T can be calculated by setting the area E. However, when the work shifts to the Q position or the R position indicated by a dotted line in FIG. 6A, the measurement point sequence data can be obtained as shown in the lower diagram of FIG.
Does not fall within the calculation region E, and therefore the feature point T cannot be calculated.

Therefore, conventionally, measurement is performed while maintaining the position of the measurement sensor 2 and the measurement area M constant, and when a measurement error occurs, the measurement area M of the measurement sensor 2 is shifted to the center of the deviation amount of the measurement target at the time of teaching. They were held nearby or the measurement area was made large enough so that measurement errors did not occur.

[0005]

However, in the former method, teaching is performed by estimating the amount of displacement.
In some cases, teaching must be performed again and again, and it takes time to teach. In the latter method, a large measurement area is required, so that the measurement process takes a long time and a large memory capacity is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and provides a measuring area correcting apparatus in a measuring apparatus capable of automatically causing a measuring area to follow a shift of a work in a lot. The purpose is to:

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a measuring means for measuring a work in a lot and extracting characteristic points thereof, and a storage means for storing an extraction result of the measuring means. A statistical processing means for statistically processing data stored in the storage means to analyze a tendency of a deviation amount of a work, and a prediction operation for calculating a predicted value of a deviation amount of the next work based on an analysis result of the statistical processing means Means, correction data calculation means for calculating data for correcting the measurement area based on the calculation result of the prediction calculation means, and displacement of the work area based on the calculation result of the correction data calculation means and the teaching data. And a correction teaching data calculating means for calculating correction teaching data to be followed.

[0008]

According to the present invention, attention is paid to the characteristic that the shift amount of a work in a lot changes with a certain tendency. In the present invention configured as described above, the measuring means measures the work in the lot and extracts the feature points. This extraction result is stored in the storage means. The statistical processing means statistically processes the data stored in the storage means to analyze the shift amount of the feature point, that is, the tendency of the work shift amount. The prediction calculation means calculates a predicted value of the deviation amount of the next work based on the analysis result, and the correction data calculation means calculates data for correcting the measurement area based on the calculation result of the prediction calculation means. The correction teaching data calculating means calculates correction teaching data for causing the measurement area to follow the shift amount of the workpiece based on the calculation result of the correction data calculating means and the teaching data. And
The measuring means is controlled according to the correction teaching data. As a result, the measurement area automatically follows the deviation of the work in the lot, and it is possible to always measure a work having a large variation.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is an operation flowchart thereof, and FIG. 3 is a diagram showing an example of a tendency of a workpiece shift.

The apparatus shown in FIG. 1 is for measuring the shape of, for example, a panel component of an automobile by using a laser beam. , And a robot 11 holding the measurement sensor 10. The measurement sensor 10 is controlled by a measurement controller 12, and the robot 11 is controlled by a robot controller 13. The measurement sensor 10 has a laser light source and a detector (such as a light receiving element) as in the conventional sensor, and is mechanically attached to the wrist of the robot 11 (FIG. 5).
reference). The measurement area is determined by the movable range of the measurement sensor 10 held by the robot 11, in other words, by the irradiation range of the laser beam. The movable range of the measurement sensor 10 can be arbitrarily given by teaching data for the robot 11. The measurement sensor 10 has a function of extracting a feature point T from the obtained measurement point sequence data (FIG. 6).
(See (B) above). The measurement sensor 10, the measurement controller 12, and the robot controller 13 are connected to an input / output interface 14, respectively.

The input / output interface 14 is connected to a feature point history data memory 15 as storage means for storing and extracting the results of the measurement sensor 10. The feature point history data memory 15 includes a statistical processing unit 16 as a statistical processing unit, a prediction operation unit 17 as a prediction operation unit, a correction data calculation unit 18 as a correction data calculation unit, and a storage medium. And a correction teaching data calculating unit 20 as correction teaching data calculating means. The correction teaching data calculation unit 20 is connected to a correction teaching data memory 21 and a teaching data memory 22 as storage media, and both the correction teaching data memory 21 and the teaching data memory 22 are connected to the input / output interface 14. Further, an operation panel 23 for operating the device and a teaching panel 24 for setting teaching data for the measurement sensor 10 and the robot 11 are connected to the input / output interface 14.

The present invention focuses on the characteristic that the shift amount of a work in a lot changes with a constant tendency for each lot. The statistical processing unit 16 stores the deviation amount in a feature point history data memory 15. Statistical processing of the feature point history data that has been performed, and the shift amount of the feature point (that is, the shift amount of the work)
Analyze trends. For example, as shown in FIG. 3, a change in the shift amount of the feature point with respect to the work row in the lot is graphed to recognize the shift amount (or variation) tendency of the work.

The prediction operation unit 17 calculates a predicted value of the shift amount of the feature point of the next work based on the analysis result of the statistical processing unit 16. Specifically, for example, as shown in FIG. 3, a calculation sample range S is set, and a predicted value Tp of the shift amount of the next feature point is obtained from a differentiated change rate within the range S.

The correction data calculator 18 calculates the predicted value Tp
The data for correcting the measurement area based on the preset teaching data is calculated based on the teaching data so that the workpiece is located in the measurement area or at a predetermined position (for example, near the center) in the measurement area. This correction data is stored in the correction data memory 19.
Is stored in

The correction teaching data calculating section 20 calculates correction teaching data based on the correction data and the teaching data. The correction teaching data has a content that causes the measurement area to follow the shift amount of the work so that the work is located within the measurement area or at a predetermined position (for example, near the center) in the measurement area. The correction teaching data is stored in the correction teaching data memory 21.

Next, the operation of the above-configured apparatus will be described with reference to the flowchart of FIG. In the present invention, focusing on the characteristic that the deviation amount of the work in the lot changes with a constant tendency for each lot as described above,
The characteristic is statistically analyzed to follow the measurement area.

First, the operator preliminarily operates the measuring panel 10 and the robot 1 for each lot using the teaching panel 24.
The teaching data for 1 is set and stored in the teaching data memory 22 via the input / output interface 14. Thereafter, when the apparatus is started by the operator through the operation panel 23, or when the measurement operation for the previous lot is completed and the next lot is switched to, the control unit (not shown) resets the work number n in the lot to 1. Initial settings such as are performed (S1).

Then, the control section determines whether or not the number n of the workpiece to be measured next is greater than 1 (S
2) If n = 1 as a result of this determination, that is, in the case of the first work of the lot, the measurement controller 12 performs a measurement operation with a sufficiently large measurement area so that a measurement error does not occur. And robot controller 1
3 (S3). The data at this time is set in advance as a part of the teaching data and stored in the teaching data memory.

On the other hand, if the result of the determination in step 2 is n> 1, the control unit uses the correction teaching data stored in the correction teaching data memory 21 as the execution teaching data and the measurement controller 12 and the robot controller. 13 to perform a measurement operation in a measurement area based on the correction teaching data (S4).

Then, when the measurement operation is completed in either step 3 or step 4, the measurement sensor 1
0 extracts the feature point T from the obtained measurement point sequence data (see the upper diagram in FIG. 6B), and stores the extraction result in the feature point history data memory 15 via the input / output interface 14 ( S5).

Then, the statistical processing section 16 statistically processes the characteristic point history data stored in the characteristic point history data memory 15 to analyze the tendency of the deviation amount of the characteristic point (that is, the deviation amount of the work) ( (See FIG. 3) (S6), the prediction calculation unit 17 calculates a predicted value Tp of the shift amount of the feature point of the next work based on the analysis result of the statistical processing unit 16 (S6).
7). For example, as described above, the calculation sample range S
Is set, and the predicted value Tp of the deviation amount of the next feature point is obtained from the differentiated change rate within the range S (see FIG. 3).
Then, the correction data calculation unit 18 corrects the measurement area based on the preset teaching data based on the predicted value Tp obtained in step 17 so that the work is located in the measurement area or a predetermined position in the measurement area. The correction data is calculated, and the correction data is stored in the correction data memory 19 (S8). Then, the correction teaching data calculation unit 20
Based on the correction data stored in the correction data memory 19 and the teaching data stored in the teaching data memory 22, the measurement area is shifted so that the workpiece is located in the measurement area or a predetermined position in the measurement area. The correction teaching data having the content to follow the amount is calculated, and the correction teaching data is stored in the correction teaching data memory 21 (S9). As described above (refer to S4), the measurement area for measuring the next work is determined using the corrected teaching data as the execution teaching data, so that the measurement area follows the deviation amount of the work, and the work is always measured. The measurement is performed at a predetermined position (for example, near the center) in the area or the measurement area. Therefore, no measurement error occurs.

Then, after incrementing the number n by 1 (S10), the control unit judges whether the updated number n is larger than N (where N is the total number of works in the lot) (S10). S11). If n> N as a result of this determination, it is determined that all the measurement work for the lot has been completed, and the routine ends.
If n ≦ N, the process returns to step 2 to execute the measurement work for the next work.

Therefore, according to the present embodiment, in the measurement of panel parts, etc., attention is paid to the fact that the deviation amount of the work in the lot changes with a certain tendency for each lot, and the characteristic of the measurement sensor 10 is used. The deviation amount of the next feature point (that is, the deviation amount of the next work) is predicted from the trend analysis of the point extraction result, and the data is fed back to the teaching data to calculate the correction teaching data. 12 and the robot controller 13 are controlled so that the measurement area automatically follows the deviation of the work. Therefore, even for a work having a large variation, the work is always within the measurement area (for example, near the center).
And measurement errors are eliminated. Therefore, it is not necessary to determine the measurement area at an optimum position in advance, and teaching becomes easy. In addition, since the measurement area follows the deviation of the workpiece, it is not necessary to increase the measurement area in advance.
The measurement processing is speeded up, and can be performed with a small memory capacity.

[0024]

As described above, according to the present invention, when measuring a work in a lot, the measurement area is made to follow the deviation of the work, so that the measurement area is expanded even for a work having a large variation. Measurement can be performed without any trouble, teaching can be simplified, measurement processing can be speeded up, and memory capacity can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is an operation flowchart of the embodiment.

FIG. 3 is a diagram illustrating an example of a tendency of a workpiece in a lot to shift;

FIG. 4 is a schematic configuration diagram of a non-contact type panel measurement device.

FIG. 5 is a schematic diagram showing a part of a measurement sensor.

FIG. 6 is a diagram for explanation of a conventional technique;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Measurement sensor 11 ... Robot 12 ... Measurement controller 13 ... Robot controller 15 ... Feature point history data memory (storage means) 16 ... Statistical processing part (statistical processing means) 17 ... Prediction calculation part (prediction calculation means) 18 ... Correction data Calculation unit (correction data calculation unit) 20: correction teaching data calculation unit (correction teaching data calculation unit) 22: teaching data memory

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-297011 (JP, A) JP-A-62-288695 (JP, A) JP-A-63-261102 (JP, A) JP-A-63-261102 44104 (JP, A) JP-A-62-54115 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 102 G01B 21/00-21/32

Claims (1)

(57) [Claims] 1. A measuring means for measuring a work in a lot and extracting a characteristic point thereof, a storage means for storing an extraction result of the measuring means, and a shift amount of the work by statistically processing data stored in the storage means. Statistical processing means for analyzing the tendency of the following; predictive calculating means for calculating a predicted value of the deviation amount of the next workpiece based on the analysis result of the statistical processing means; and a measurement area based on the calculation result of the predictive calculating means. Correction data calculation means for calculating data to be corrected; correction teaching data calculation means for calculating correction teaching data for causing the measurement area to follow the deviation amount of the work based on the calculation result of the correction data calculation means and the teaching data; A measurement region correction device in a measurement device, comprising: