JPH03142356A - Ultrasonic flaw detector - Google Patents

Abstract

PURPOSE:To efficiently detect flaws of an object to be detected with a high precision by emitting an ultrasonic flaw detecting signal to the rotating object by an ultrasonic probe and receiving the reflected wave. CONSTITUTION:A rotating means 501 is rotated around a prescribed rotation axis in a three-dimensional coordinate system to rotate an object W to be detected which is put on the means 501. An ultrasonic probe 502 emits the ultrasolic flaw detecting signal to this object W and receives the reflected wave. An attitude control means 504 controls the position and the attitude of the probe 502 so that the ultrasonic flaw detecting signal is made incident at a prescribed angle on a prescribed point of the object W from a prescribed distance. A distance detecting means 503 detects the distance from a distance measuring point on the object W, and a position detecting means 505 detects the position of the means 503. A position and attitude arithmetic means 506 calculates position information of the distance measuring point on the object W based on detection results of means 503 and 505 to calculate the position and the attitude of the probe 502. A control means 507 executes scanning in the peripheral direction of the means 503 and scanning for flaw detection in the peripheral direction of the probe 502.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an apparatus for detecting flaws in a test object with an ultrasonic probe by rotating the test object, which has a substantially cylindrical shape.

B. Conventional technology Journal of Japan Society of Mechanical Engineers vol. 1.90. &826゜p5
~9 (Conventional Document 1) and Nondestructive Inspection Vol. 37 No. 2 P15
The water immersion automatic flaw detection method shown in No. 2 to No. 153 (Conventional Document 2) is known. This is for the purpose of precise ultrasonic flaw detection, in which an ultrasonic probe is scanned over the surface of a test object in water in which the test object is immersed. In this automatic water immersion flaw detection method, in order to accurately determine the size and location of flaws (defects), the distance between the ultrasonic probe and the test object is kept constant, and the direction of the central axis of the ultrasonic beam is must be aligned with the normal direction of the surface of the subject.

The device disclosed in Conventional Document 1 is capable of detecting flaws on a specimen whose surface ml is flat, but when the surface is curved, it is difficult to align the direction of the central axis of the ultrasonic beam with the normal direction of the surface of the specimen. Because of the difficulty in detecting flaws on objects with curved surfaces, it was not possible.

On the other hand, the apparatus disclosed in Conventional Document 2 first measures the shape of the entire surface of the object using a laser distance meter.

Next, the shape data is used to scan the ultrasonic probe, allowing flaw detection on objects with arbitrary surface shapes.

Problems to be Solved by the C0 Invention However, with the conventional apparatus of Document 2, it is impossible to detect flaws in a cylindrical object as it is.

Therefore, as shown in FIG. 20, when the object W is a cylinder, the object W is rotated by a rotary drive device 101, and an ultrasonic probe is moved in the X, Y, and Z axis directions by an active device 102. Using the child 103, flaw detection is performed, for example, in one of the following procedures.

(1) Move the X, Y, Z drive device 102 to align the ultrasound probe 103 in the normal direction of the surface of the subject at the scanning start end (for example, point A in FIG. 20).

Drive the X-axis to move the ultrasound probe 103 to the scanning end (second
Detect flaws by moving to point B in Figure 0). The subject W is rotated by a small angle using the rotation drive device 101. Flaw detection is performed by repeating the operation of moving the ultrasonic probe 103 to point A by driving the X axis.

(2) After aligning the ultrasonic probe 103 in the normal direction of the surface of the object, flaw detection is performed while rotating the object W once. The ultrasonic probe 103 is slightly moved in the X-axis direction. The flaw detection operation is repeated while rotating the object W once again.

However, if the center of the object W and the center of rotation deviate even slightly, or if the object W is a rotating body with a complicated shape, it is impossible to perform flaw detection.

A technical object of the present invention is to enable flaw detection of a rotating body having a complicated shape to be performed in parallel with shape measurement.

Means for Solving Problems No. 96 To be explained with reference to FIG. 1, which is a diagram corresponding to the claims, the present invention rotates around a predetermined rotation axis in a predetermined three-dimensional coordinate system and a mounted subject W. Rotating means 501 for rotating
an ultrasonic probe 502 that emits an ultrasonic flaw detection signal toward the rotating object W and receives the reflected wave; Attitude control means 504 controls the position and attitude of the ultrasonic probe 502 so as to make the ultrasonic probe 502 incident at an angle; a distance detection means 503 that detects the distance to a distance measurement point on the subject while maintaining a constant positional relationship under the position and orientation of the ultrasound probe 502 controlled by the position and orientation control means 504; Position detection means 50 that detects the position of distance detection means 503 in a three-dimensional coordinate system
5, the detection result of the distance detection means 503 and the position detection means 5
The position information of the distance measurement point on the subject is calculated based on the detection result of 05, and the ultrasound probe 502
It is equipped with a position/orientation calculation means 506 for calculating the position and orientation of the sensor, and a control means 507 for causing circumferential scanning by the distance detecting means 503 and circumferential flaw detection scanning by the ultrasonic probe 502 to be performed in parallel. .

The apparatus according to claim 2 has a storage means for dividing the surface of the subject into small regions defined by rotation angles and positions in the direction of the rotation axis and storing only one piece of positional information calculated for each small region, The position and orientation of the ultrasonic probe are calculated based on position information within a small area corresponding to each circumferential flaw detection scan.

E0 effect subject W is rotated around a predetermined rotation axis by rotation means 501. The distance detection means 503 measures the distance to a distance measurement point on the rotating subject. Before starting the flaw detection operation, shape measurement is performed by scanning the surface of the object while controlling the position and orientation of the distance detecting means 503 based on, for example, the known shape of the object.

If the surface shape of the object is not known, the distance detection means 503 may be scanned along the surface.

The position and orientation of the ultrasound probe 502 are calculated based on the position information of the measurement points of the subject W measured in this way, and
The ultrasonic probe 502 is controlled to such a position and attitude. In this state, an ultrasonic flaw detection signal is emitted toward the object W at a desired angle of incidence, and the object W is flaw-detected by the reflected wave therefrom.

In parallel with this flaw detection operation, the distance detection means 503 detects the distance to the shape measurement point on the line preceding the flaw detection scanning line. Based on the preceding shape measurement results, the position and orientation of the ultrasonic probe 502 when it next performs flaw detection scanning on the scanning line or on a line in the vicinity thereof is calculated.

In the apparatus of the second aspect, the position and orientation for the flaw detection operation are calculated from the position information within the small area.

Therefore, the position and orientation of the ultrasonic probe 502 can be calculated so as to perform flaw detection on a scanning line different from the scanning line for measuring the shape of the surface of the object.

F. Embodiment 1 First Embodiment - [Description of the entire apparatus] The entire flaw detection apparatus to which the present invention is applied will be explained with reference to FIGS. 2 to 16.

As shown in FIGS. 2(a) and 2(b), this flaw detection device consists of a gate-shaped traveling body 2 that travels in the X-axis direction by an It has a Y-axis traveling body 4 that travels by a Y-axis drive device I3, and a Z-axis arm 7 that moves up and down in two axial directions by a IIIM movement W6 is provided on a bracket 5 that is integrated with the Y-axis traveling body 4. . A wrist portion 8 of the robot is attached to the lower end of the Z-axis arm 7. The cylindrical object W is placed on the turntable TB and is rotatable about the rotation center in the Z-axis direction.

As shown in FIG. 3, the wrist portion 8 is connected to a β-axis rotation drive device 8B provided in a housing 8A fixed to the lower end of the two shafts 7, and a rotation shaft of this β-axis drive device 8B. It has a bracket 8C and an α-axis rotation drive device i8E, which is attached to the bracket 8C and has a bracket 8D attached to its rotating shaft. The toucher 9 and one distance sensor unit 10 that detects the surface position of the subject W are attached in a positional relationship separated by L in the Z-axis direction. The distance sensor unit 10 can be composed of, for example, an ultrasonic probe, and its detection signal is input to a distance detection circuit 11 shown in FIG.

As shown in FIG. 4A, the distance detection circuit ↓l includes a transmitter 11a that transmits an ultrasound signal to the ultrasound probe 10, and a receiver 11b that receives the ultrasound signal reflected from the subject W.
and from the clock circuit 11c. The clock circuit 11c measures the time interval between the transmission signal from the transmitter 11a and the ultrasound reflected signal from the surface of the subject W, and outputs the result to the control device 12.

Here, the time interval is t. , the distance M between the ultrasound probe 10 and the surface of the subject W is given by V, the speed of sound in water.

M=Vt,/2...calculated by (1).

Furthermore, in FIG. 2, the control device W12 is a CPU.

It is a microprocessor consisting of ROM, RAM, etc., to which the detection signal ST from the ultrasonic probe 9 and SW indicating the time interval from the distance detection circuit 11 are input, and x, y, z, β, α-axis drive drive ll, 3, 6.8B
, SEL, - signals SX, SY, from integrated position or angle detectors, e.g. potentiometers (not shown);
SZ, Sβ.

Sα is also input. 13X, 13Y, 13Z.

13α, 13β are the driving devices for each axis 1, 3, 6° 8B, 8
E is an active servo amplifier, 14 is an input device for inputting the flaw detection range, etc., and 15 is a recorder for recording the flaw detection results. Note that each shaft drive device includes, for example, an electric motor. Further, 16 is a drive device for rotating the turntable TB, and controls the rotation angle of the turntable TB in response to a command signal from the control device 12. Reference numeral 17 denotes an angle detector built into the drive device 16, and its angle signal Sγ is input to the control device 12.

[Arithmetic processing of the control device 12] In this embodiment, the center position of the turntable TB is set as the coordinate origin O, and γ0. γa and DI are defined as shown in FIG. 4B. Here, γ0 is the angle between the detection direction of the distance sensor unit 10 and the X-axis at a given time, and Ya is the measurement point and coordinate origin at which the ultrasonic signal from the distance sensor unit 10 hits the surface of the subject W at that time. The angle between the line connecting O and the detection direction of the distance sensor unit 10, Dl
is the distance between the measurement point and the coordinate origin, which is indicated by (Xa, Ya, Za).

■Main flowchart FIG. 5 is a main flowchart of the arithmetic processing executed in the control bag % (12).

First, initial processing such as memory is performed in step S10, and then, in step S20, the ultrasound probe 10 is positioned to a control start position. FIG. 6 shows a state in which the positioning operation is completed. Then, the process moves to step S30, where the ultrasonic probe 10 is aligned in the normal direction on the measurement point of the object W based on the surface shape data of the object W known in advance from the design specifications, etc. The surface of the subject W is rotated and scanned by rotating the turntable TB.

This rotational scanning is performed a plurality of times at a predetermined pitch in the Z direction to collect surface shape data in at least the distance range shown in FIG. 3 in more detail than the design data given in advance prior to flaw detection. That is, the surface shape of the subject W is determined by the signal sx from the position or angle detector built into each axis parking device.
, sy, sz.

Calculations are performed for each scanning line based on Sα, Sβ and the signal SW from the ultrasound probe 10. The detailed procedure is shown in FIG.

Next, when this shape measuring operation is completed, the process advances to step S40 to proceed to a flaw detection operation procedure. Here, step 830
Based on the surface shape data of the object W obtained in Ultrasonic probe 9 at the timing when 9 is controlled to each control point.
During this flaw detection operation, the ultrasonic probe 10 scans several lines (distance 111L in FIG. 3) ahead of the ultrasonic probe 9, and the The distance between the probe 10 and the subject W is calculated, and the position data from the position or angle detector described above as well as the surface shape data of the preceding scanning line are collected. When the ultrasonic probe 9 reaches the scanning line, position information of the control point of the ultrasonic probe 9 corresponding to the flaw detection point on the preceding scanning line is calculated from this collected data, and The detailed procedure for flaw detection is shown in FIG.

When this flaw detection operation is completed, the ultrasonic probe 9 is moved to the end position in step S50, and the process ends.

Next, the shape measurement operation and flaw detection operation will be explained in detail.

■Flowchart of shape measurement operation FIG. 7 shows details of the shape measuring operation in step S30.

First, in step S31, command values for one rotation of each drive device (hereinafter referred to as each axis command value) are taken in and stored in the memory. The command value for each axis for one rotation is expressed by formula (2) ~
The data group is shown in (6).

Xr= (Xs, x, ...++..., xn,"
"", xllaX)"' (2) Yr= (Ys, Y
,, −, Yn, −, Ymax)・−(3) Zr= (Z
s* Zx+ −−+ ZJ”””IZIlaX)
”' (4) αr= (αS, α11 ”””l
αn, ""'", α sum a s)°'. (5) βr-
(βS, β1..., βn,..., β
wax)...(6) γr= (γS, γ1...
・Yn,...γWaX)... (7) Here, γr is the angle command value of the turntable TB.

These axis command values require less precision than the command values for flaw detection operations, which will be described later. Therefore, the positions of representative points on the one-rotation scanning line are determined based on the design data of the object W, and interpolation is performed between them. is required.

Next, in step S32, positioning is performed to the scanning start point. That is, Xr=Xs, Yr=Ys, Zr=Zs+CEr
=(*S+ βr=β!3+ yr=ys (=O
) and position each axis. After this positioning is completed, the variable N is set to 1 in steps S3, 3, and step S3
When the process proceeds to step 4 and outputs the object rotation command, the timer interrupt program shown in FIG. 8 operates at regular intervals.

In FIG. 8, first, in step 5341, it is determined whether or not there is a command to stop the object. Since the first command is the object rotation command, the process moves to step 5342, and the Nth command value, that is, N
=1 command value Xr=X 8. ,Yr=Y,,Zr
=Z1. ar=a8. βr−β,.

Take in γr=γ. Then, signals SX, SY, SZ, Sa, and Sp indicating the current position of each axis described above.

Sγ is taken in from each detector and the current value of each axis is X0°Yo.
tZ,,α. ,β. , γ. Find the command value and the current value of each axis X0. Yo, Zo, α. ,β. , γ. A so-called servo calculation is performed by calculating the difference between the two and multiplying the deviation by a certain coefficient, and outputs the calculation result to servo amplifiers 13X to 13β and 13T in FIG. As a result, the distance sensor unit 10 moves to the first commanded position. At this time, the ultrasonic probe 10 faces in the normal direction of the surface of the measurement point on the subject W. Then, in step 5343, the distance Qa between the ultrasound probe 10 and the surface of the subject W is acquired using the signal SW from the distance detection circuit 11. Next, in step 5344, signals SX, SY from the detectors of each axis drive device are detected.

Take in SZ, Sα, Sβ, Sγ, step 5345
The current value of each axis is XotY,,Z,,α. ,β. .

γ. The position (Xa) of the point on the surface of the subject W that is hit by the ultrasonic beam of the ultrasound probe 10 is determined.

Ya, Za) and the angle γa of the turntable TB at the point hit by the ultrasonic beam. Here, Xa-
Za and Ya are calculated from the following relational expression.

Xa=f, (Xo, Yo, Zo, α., β0.
Qa) ・(7) Ya= fz (XOI Yllll
Zol ao+ β. ,Qa)−(8)Za”f
i (Zol Yo+ Zol Qo+ β.

, 12a) −(9)ya=f4 (Xa, Ya,
To) - (10) Furthermore, the length Di from the Z-axis coordinate axis of a point on the surface of the subject W that is hit by the ultrasound beam is calculated by the following equation.

DI=Xa+Ya"...(1
00) Next, in step 8346, equations (7) to (
10), the surface position of the subject W determined in (100) is stored. An example of a method for storing this position will be explained using FIG. 9.

Figure 9 shows area division for position memory.
The horizontal axis is the angle γ of the turntable TB, and the vertical axis is the biaxial coordinate. In the figure, the shaded area is the flaw detection range in two coordinates of the object W.

The position memory area is a slightly larger area than the flaw detection area, and the area (γ axis is O ~ 360', Z axis is zth ~
z th,) is divided into (P+1) in the γ-axis direction and (S+1) in the Z-axis direction to form a plurality of small regions.

And Za obtained by formulas (9) and (10).

It is determined which small area in FIG. 9 Ya belongs to, and Za, Dl are used as the position data of the small area to which it belongs.

Ya and a flag indicating storage completion are stored.

Here, in each scan of one rotation in the shape measurement operation, the angle in the γ-axis direction of the (P+1) divided small area is larger than the scanning pitch angle in the γ-axis direction, so we try to store the measurement data for each scan. In this case, two or more pieces of data are stored in each small area, and there is no point in partitioning the small areas.

Therefore, the position data obtained in the current scan (for example, the scan when N=CI) is the same as that in the previous scan (for example, the scan when N=Q-1).
(1) If it is determined that the area belongs to a small area that has already stored position data, since only one position data needs to be stored in each small area, (1) Update the stored contents using the new position data obtained as stored data 6 (2) The stored contents are not updated by using the old position data already obtained as stored data.

(3) Update the storage contents by using the average value of the new data and the old data as new storage data.

You may also use a method such as

Next, the program procedure moves to step 5347 in FIG. 8, adds 1 to variable N, and ends as N22.

When the operation of the timer interrupt program in FIG. 8 is completed, the program procedure returns to step S35 in FIG.
It is checked whether one rotation scan is completed based on whether or not is (max+1). At this stage, it is N22, so step S35 is repeated, and during this time, the timer interrupt program shown in FIG. 8 operates at a certain time interval, and the subject W is rotated by the turntable TB as shown in FIG. 10. scanned. Along with this scanning, the surface shape DI and Z of the subject W are stored using the storage method described above.

The γ position coordinates are stored.

When the one-rotation scan is completed and N=II+ax+1, the program moves from step S35 to step 836, and outputs a scan stop command. With this stop command, the procedure of the timer interrupt program shown in FIG. 8 advances to step 8348, where Xmax, which is the last command value in
Ya+ax, Zmax, amax.

βll1ax and γwax (=360") are taken in, servo calculation is performed, and the calculation result is sent to the servo amplifier 13.
Output to X~13β, 13T.

When one rotation of scanning is completed in this manner, the process proceeds to step S37 in FIG. 8, where it is determined whether the shape measurement operation is completed. In this embodiment, the ultrasonic probe 10 detects Z
Surface shape data on a rotating scanning line that precedes by a distance of 1 mtL in the direction is collected, and scanning control points for the flaw detection ultrasonic probe 9 are calculated based on the results. therefore.

In order to perform flaw detection on the object W by sequentially controlling the ultrasonic probe 9 to move back and forth to a plurality of control points on a certain rotational scanning line according to the position data obtained by such a shape measurement operation, at least Until the ultrasound probe 9 reaches the first rotation scanning line of the ultrasound probe 10, that is, until the ultrasound probe 9 moves down in the Z direction by L shown in FIG. It is necessary to repeat rotational scanning for shape measurement.

Therefore, since the shape measurement scan is not completed after the second round of shape measurement scans, the program moves from step S37 to step S31, takes in each axis position command for the next one rotation scan, and repeats steps 832 to 37.

As shown in FIG. 11, the ultrasonic beam of the ultrasonic probe 9 is memorized by the shape measurement operation shown in FIG. It is determined that the measurement operation is complete, and the program returns to the seventh step.
The process moves from step S37 in the figure to the flaw detection operation in step S40 in FIG.

By the operation of only shape measurement before the flaw detection operation explained above,
The coordinates of the surface of the subject W in the area indicated by the single point II4 line in FIG. 11 are stored by the storage method shown in FIG.

■Flow chart of flaw detection operation Next, the flaw detection operation processing in step S40 in FIG. 5 will be explained.

FIG. 12 is a detailed flowchart of the flaw detection operation processing procedure S40, which is similar to the flowchart of the shape measurement operation in FIG. First, in step S41, each axis position command value for one rotation scan of the flaw detection probe 9 is calculated. The calculation will be explained in detail with reference to FIGS. 13 and 14.

FIG. 13 is a flowchart of the calculation procedure for each axis position command value for one rotation scan in step 541, and FIG.
FIG. 6 is a diagram illustrating which data of the stored position data on the surface of the subject W is used when calculating each axis position command value. The thick solid line in FIG. 14 is the flaw detection scanning line by the ultrasonic probe 9, and the processing in FIG.
The command values for each axis at the control point positions shown in . . . are calculated.

In FIG. 13, in step 5411, the normal vector of the surface of the subject W in the vicinity of the control point position is calculated.For example, in the case of the control point position .

Neighboring area (1,P), (1,0) containing the first .
, (2, O), and (2, P), it is found that if the data of the four regions are all in the close vicinity of , there is a detection error in the surface position of the object W. This is undesirable because the line vector calculation error becomes large. Therefore, the outer areas (0, P-1), (0, 1), (3
, 1) and (3, , P-1) will be used. The data of the area (0, P-1) is converted to Xi, Yl, Zi, and the data of the area (0, 1) is converted to X'2, Y2, '7.
2. Data of area (3,1) is converted to X3. Ya, Z3, data of area (3, P-1) to X4. Y4. Assuming Z4,
The normal vector N (=Nx, Ny, Nz) in the vicinity of the control point position on the surface of the subject W is determined by the following equation.

Nx=Σ(Yi−Yj) X (Zi+Zj) −(1
1) NY=Kei (Zi-Zj) X (Xi+Xj)...
・(12) Nz=±(Xi-Xj) X (Yi+Yj
)...(13) However, if l≠4, then j=i+1. i=
If it is 4, then j=■.

Note that X1 to X4. Yl to Y4 are obtained by converting from the angle γa and the length DI using the following formula before calculating the normal vector.

X1==DIsin(Ya-Y)...(101
)Y1=DIcos(γa-γ)...(102)
Next, in step 5412, position calculation of the control point position is performed. The position of the control point in Fig. 14 is (Xk, Yk
, Zk), Zk is a value given to set the storage area and is known. Also.

Since the center coordinates of the turntable TB are (0, O, O), Yk=O and Yk is also known.

Therefore, the position calculation of the control point position in step 5412 is
This is an operation to find k.

Now, as shown in FIG. 5, the plane PL including the control point position in a certain coordinate system is expressed by the following plane equation.

NxX+NyY+NzZ+d=O-(14) Therefore, normal vector N (=Nx
, Ny, Nz), the coordinates (, Xm, Ym,

Zm), the coefficient d of the plane equation of the plane PL is given by the following equation.

d = -(NxX+s+NyY+a+NzZm)...
(15) By using this coefficient d, the digit g (Xk), which is the first control point, can be found as follows.

Xk=-(d 10NyYk+NzZk)/Nx-(16
) Next, it is used to calculate the coefficient d (X m, Y 1
1°Zm) will be explained.

The calculation of the normal vector is performed in the area (0, P−
1), (0,1), (3,1), and (3°P-1), but the stored data used to calculate the coefficient d is near the control position of . is close to the true value. Therefore, the areas (1°P), (1,,0), (2,O), (
2. Use the stored data of P). That is, the area (1,
P)'s stored data and the normal vector obtained from equations (11) to (13) are substituted into equation (15), and the value is calculated as d
Let it be l. In the same way, d2 is the value calculated from the stored data in area (1, O), d3 is the value calculated from the stored data in area (2, O), and is the value calculated from the stored data in area (2°P). d4, and calculate the coefficient d as an average value using the following equation.

d= (d1+d2+d,+d4)/4...(17)
By averaging the coefficients obtained from the four regions in this way, the coefficient d of the control point becomes close to the true value.

From the above explanation, the normal vector N(”Nx
+ Ny, Nz) and place! (Xk, Yk, Zk)
was found.

The program procedure in FIG. 13 then moves to step 5413, where the position command values for each axis are calculated and stored. Here, the distance between the ultrasound probe 9 and the surface of the object W becomes i. When set as follows, the position command value of each axis (Xr, Yr,
Zr, ar, ar) are calculated from the following relational expression and stored.

Xr=f, (Xk, Yk, Zk, Nx, Ny, NZ, L
)-(18) Yr=fG(Xk, Yk, Zk, Nx, N
y, Nz, Q, )-(19) Zr=f, (Xk, Yk,
Zk, Nx, Ny, Nz, Qo) - (20) αr=f,
(Nx, Ny+ Nz) =-(
21) βr=f, (Nx, Ny, Nz)
(22) At the same time, the angle command value γr of the turntable TB at the control point is also stored.

Next, the process moves to step S414, and it is determined whether calculations for one rotation scan have been completed. Of course, in the above explanation, only the control points indicated by . in FIG. 14 have been calculated, so the process returns to step 5411 to calculate the normal vector in the vicinity of the next 0 control point. In this way, by sequentially repeating the processing of steps 8411 to 414, calculations are performed up to the control point positions marked .~O in FIG. 15, and the procedure in FIG. 13 is completed, and step S4 in FIG.
Move on to 2. At this time, each axis position command value for one rotation scan is a data group expressed by equations (23) to (26).

Xr= (XrB, Xrt+ ”'xrn+...4
rmax) −(23)Yr= (Yrs, Yrx+
-Yrn, -Yrmax) -(24)Zr= (
Zrs+ Zr, -=Zrn, -Zrmax)
...(25) αr” (CEr31 αrl + ”
'CErn,"' (XrllaX) "' (26
) βr= (βfs+ βrx+...βrn,...
βr+aax)...(27)yr=(γrSeγrl
-1"'γrn, '-・Yrmax) - (28) The processing of steps 842 to S45 in FIG. This is carried out using a data group of command values.Similarly to the shape measurement operation, steps S42 and 43 are executed, and when an object rotation command, that is, a scan start command is issued in step S44, the timer shown in FIG. The allocation program is started.

In step 5441 of the program in FIG. 16, it is determined whether or not the rotation has stopped. If the answer is negative, in step 5442, the Nth axis position command value is taken in, servo calculation is performed, and output is performed. Thereafter, the process proceeds to step 5443, where the direction of the ultrasonic probe 9 is taken in and the flaw detection results are transferred to the control point 11 ('Zr.

γr) to the recording device 15.

Next, steps 8444 to 8448, which are similar to steps 8343 to 5347 in FIG. 8, are sequentially executed to measure the shape of the scanning line preceding the distance shown in FIG. 3 in parallel with the flaw detection operation.

When one rotational scan is completed by repeating such a procedure, the process proceeds from step S45 to 346, and a command to stop the object is output. Then, when it is determined in step 5441 that scanning is to be stopped, in step 5449, the N-waxth axis position command value is taken in, servo calculation is performed, and output is performed. and.

Proceeding to step S47, it is checked whether the flaw detection operation has been completed. That is, it is checked whether the entire range indicated by the thick solid line in FIG. Calculate the axis position command value.

After scanning the entire flaw detection range shown in FIG. 9, the program moves from step S47 to step S50 in FIG.
Move to, position each axis to a certain end position,
Control is complete.

As described above, in the embodiment described with reference to FIGS. 2 to 16, the measurement of the surface shape of the object W and the flaw detection operation are performed in the following manner.

(a) The subject is rotated.

(b) The posture of the distance sensor unit is controlled based on data on the surface shape of the object given in advance, and a distance detection ultrasonic signal is emitted toward the rotating object. Then, the distance from the reflected wave to the distance measurement point on the surface of the subject is measured.

From the distance data and the current position of the distance sensor unit, position information of the measurement point on the subject, that is, shape measurement data is calculated.

(c) The shape measurement data is stored as data for one of the small regions defined by the rotation angle of the turntable and the two-axis coordinates. However, only one piece of data is stored within the small area.

(d) Repeat steps (b) and (c) for the distance shown in FIG.

(e) Find the position command value (probe position and orientation) of the control point of the flaw detection probe from the surface shape data of the object W stored in each small region in (b) to (d). .

(f) Control each axis drive device using the position command value to control the position and orientation of the flaw detection probe so that the ultrasonic flaw detection signal is directed in the normal direction of the object surface and a predetermined distance. .

(g) At that position and attitude, the flaw detection probe emits an ultrasonic flaw detection signal to detect flaws in the object.

(h) In parallel with this flaw detection operation, the distance sensor unit emits an ultrasonic signal toward the object to collect shape measurement data on a scanning line that precedes the flaw detection probe by a distance. This shape measurement data is used to calculate the position and attitude of the flaw detection probe when it reaches on or near the scanning line.

Therefore, the flaw detection probe can always be accurately directed at a predetermined distance from the surface of the rotating object and in the normal direction, making it easy to detect flaws in rotating objects with irregular surface shapes. Furthermore, since the flaw detection operation and the shape measurement operation are performed in parallel, the measurement time is shortened.

Furthermore, the area for storing one position data is divided into small areas based on the rotation angle of the turntable and the Z coordinate, and only one position data is stored in each area. Since the control point of the probe is determined, the memory capacity can be reduced.

You can freely set a scanning line different from the opening and shape measurement scanning line for flaw detection. As a result, the degree of freedom in flaw detection operation is increased, and the arrangement of the flaw detection probe and the distance measurement probe is not restricted.

In addition, in the configuration of the above embodiment, the turntable T
B is the rotation means 501, the distance sensor unit 10 and the distance detection circuit 11 are the distance detection means 503, each axis drive device is the position and attitude control means 504, and the position or angle detector of each axis drive device is the position detection means. 505, the control device 12 calculates the position and orientation calculation means 506 and the control means 507.
and constitute respectively.

Modified Embodiment> In the above embodiment, at the start of flaw detection scanning of an arbitrary line, the position command value of each control point of the line scanning is calculated. Therefore, there is a loss time during which the ultrasonic probes 9 and 10 are stopped until the actual flaw detection operation is started. Therefore, in this modification, the position command value for the next line scan is calculated in advance during each flaw detection operation to eliminate the loss time.

This will be explained with reference to FIGS. 17 to 19.

Fig. 17 shows the hardware configuration when there are two central processing units. 31 is the central processing unit, which is responsible for calculating the command value of each axis for one scan in the flaw detection operation, and for other processing. is performed by the central processing unit 32. 33 is a memory for storing position data on the surface of the object and a calculation start flag for each axis command value for one scan, and 34 is a memory for storing each axis command value calculated by the central processing unit 31 and a calculation completion flag. be.

FIG. 18 shows the flaw detection operation (12th
(instead of diagrams) with detailed flowcharts.

FIG. 19 is a flowchart of the central processing unit 31.

Next, the operation of this modified embodiment will be explained.

First, in step 5101, a scan counter CN is set to 1, and a command calculation start flag is set in the memory 33.

Then, the process waits until the computation completion flag is set in step 5102.

The process in FIG. 19 first waits until the computation start flag is set in step 5201. If the calculation start flag is set in step 3101 of FIG. 18, the process proceeds to step 5202, reads the count value of the scan counter, and resets the calculation start flag and calculation completion flag in the first step 5203. Note that, as a matter of course, the calculation completion flag is initially reset.

Then, the process moves to step 5204, in which each axis command value of the scan line corresponding to the value of CN, that is, the first scan line is calculated. This calculation is exactly the same as the calculations in steps 8411 to 5414 in FIG. 13. Then, in step 5205, the obtained axis command values are stored in the memory 34.
At the same time, in step 8206, the calculation completion flag is set in the memory 34, and the process returns to step 5201.
Waits for a command to start calculating the command value for the next scanning line.

By setting the computation completion flag, the program in FIG. 18 proceeds from step 5102 to step 5103, where each axis command value is fetched from the memory 34.

Then, in step 5104, the count value CN of the scan counter is incremented by 1 and a command value calculation start flag is set. Further, in steps 8105 to S109, the first
Performs scanning line flaw detection operation. During this flaw detection operation, the central processing unit 31 calculates a command value for the second scanning line.

As described above, according to this embodiment, since flaw detection and command value calculation can be performed in parallel, the time from the start to the completion of flaw detection can be further shortened.

In the above, it was assumed that flaw detection was performed by directing the ultrasonic beam from the flaw detection probe in the normal direction of the surface of the object to be inspected. For example, the present invention can be applied to flaw detection by directing an ultrasonic beam in the surface wave critical angle direction.

Furthermore, in the above description, the measurement point of the distance sensor unit is commanded using the design data of the object during the shape measurement operation prior to the flaw detection operation. However, if two distance sensor units are provided, for example, The shape measurement may be performed while tracing the surface shape of the specimen.

G0 Effects of the Invention According to the present invention, it is possible to accurately and efficiently detect flaws in a rotating object having a complex surface shape.

In particular, by dividing the storage area of position information into small areas and determining the position and orientation of the probe in an arbitrary scanning line from the position information of each area, the storage capacity can be reduced. At the same time, it becomes possible to perform flaw detection on an arbitrary scanning line different from the shape measurement scanning line.

[Brief explanation of the drawing]

FIG. 1 is a complaint correspondence diagram. 2 to 16 illustrate one embodiment of the present invention, and FIG. 2 is an overall configuration diagram of the control system. FIG. 3 is a diagram showing details of the mounting structure of the flaw detection ultrasonic probe and the distance sensor unit. FIG. 4A is a block diagram showing details of the distance detection circuit. Figure 4B shows γ0. It is a figure explaining γa and DI. FIG. 5 is the main flowchart. FIG. 6 is a perspective view showing the distance sensor unit and the subject at the initial position. FIG. 7 is a shape measurement flowchart. FIG. 8 is a flowchart showing details of the shape measurement flowchart. FIG. 9 is a diagram for explaining the flaw detection range and the storage area for position data. FIG. 10 is a perspective view showing the distance sensor unit during shape measurement operation. FIG. 11 is a perspective view showing the flaw detection probe and distance sensor unit at the start of flaw detection operation. FIGS. 12, 13, and I6 are flowcharts showing flaw detection operations. FIG. 14 is a diagram illustrating a flaw detection scanning line within a small area in which position data is stored. FIG. 15 is a diagram for explaining the coefficient d when calculating the position data of a control point from the position data of a small area. 17 to 19 explain a modified embodiment, and FIG. 17 is a block diagram showing the hardware thereof. FIGS. 18 and 19 are flowcharts showing the processing procedure. FIG. 20 is a diagram illustrating a conventional ultrasonic flaw detection device. 1: X-axis drive device 3: Y-axis drive device 6: Z@drive drive W 8B = β-axis park drive device 8E: α-axis drive device
9: Flaw detection probe 10: Distance detection probe 11: Distance detection circuit 12: Control device 16: Rotation drive device 31, 32: Central processing unit 33. 34: Memory 501 Two rotation means 503: Distance detection Means 505: Position detection means 507: Control means 502: Ultrasonic probe 504: Position and orientation control means 506: Position and orientation calculation means TB: Turntable

Claims (1)

[Claims] 1) Rotating means for rotating a placed test object by rotating around a predetermined rotation axis in a three-dimensional coordinate system; and an ultrasonic flaw detection signal directed toward the rotating test object. An ultrasonic probe that emits and receives reflected waves, and the position and orientation of the ultrasonic probe is controlled so that the ultrasonic flaw detection signal enters a predetermined point on the object from a predetermined distance at a predetermined angle. a position/orientation control means, and a distance measuring point on the subject while maintaining a constant positional relationship with the ultrasonic probe so as to scan on a scanning line preceding the ultrasonic probe; distance detection means for detecting the position and orientation of the ultrasonic probe under the control of the position and orientation control means; position detection means for detecting the position of the distance detection means in the three-dimensional coordinate system; a position where positional information of a distance measurement point on the subject is calculated based on the detection result of the detection means and the detection result of the position detection means, and the position and orientation of the ultrasound probe are calculated from the calculation result; An ultrasonic flaw detection apparatus comprising: attitude calculation means; and control means for causing circumferential scanning by the distance detecting means and circumferential flaw detection scanning by the ultrasonic probe to be performed in parallel. 2) The apparatus according to claim 1, further comprising a storage means for dividing the surface of the subject into small regions defined by rotation angles and positions in the direction of the rotation axis, and storing only one piece of position information for each small region; An ultrasonic flaw detection apparatus characterized in that the position and orientation of the ultrasonic probe are calculated based on position information within a small area corresponding to each circumferential flaw detection scan.