JPS6055282A - Method for detecting position of object to be measured - Google Patents

Abstract

PURPOSE:To detect the center position of a hole rapidly and surely in spite of a small hole by detecting one axial direction center position from a reflected signal minimum value by ultrasonic scanning and determining a virtual center position from the relative position shift of an ultrasonic wave transmitting/receiving element and reflected signal intensity. CONSTITUTION:When a reflected signal is processed by a CPU or the like by executing ultrasonic wave scanning in the X axis direction, a scanned distance/ reflected signal intensity curve is determined and the X coordinate of a hole is calculated from the scanned distance corresponding to a reflected signal minimum value P1. Simultaneously, shift value corresponding to the minimum value P1 is calculated on the basis of a relative positional relation shift/reflected signal curve between an ultrasonic wave transducer and the hole which are previously stored in a memory, the Y coordinates of two pairs of virtual centers of the holes located on comparing positions are determined and one virtual center coodinate is selected from the scanning position. Thus, the center position can be detected rapidly and surely even if the diameter of the hole is small.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for detecting the position of an object to be measured using ultrasonic waves.

Configuration of the conventional example and its problems The conventional method for detecting the shape of the object to be measured is to detect the position of the object from the intensity of the reflected signal obtained by scanning the ultrasonic source wave element with respect to the object. There is something that detects posture.

The outline of the contents will be explained below.

FIG. 1 is a system diagram showing the general configuration of a conventional device. FIG. 2 is a perspective view showing position detection using a conventional device. In FIG. 1, when a high voltage pulse 17 shown in FIG. 3 is applied to the ultrasonic transceiver element 1, an ultrasonic pulse of a predetermined frequency is emitted into the air. This ultrasonic pulse is reflected by the target object 13 in FIG.
The reflected signal from 4,15°16 reaches the ultrasonic transceiver element 1, is amplified by the transfer signal amplifier 3, and then is converted into an analog signal.
It is digitally converted and stored in the memory 6. Figure 3 shows
It shows the operating waveforms of the ultrasonic transceiver element 1 stored in the memory 6, and 37, 38, and 39 represent the target object 13, respectively.
The reflected signals from each side 14, 16, and 16 are shown. The reflected signals stored in the memory 5 are transferred to a small electronic computer 6, and the propagation time of the reflected signals 37, 38, 39 shown in FIG.
is being detected.

In addition, in FIG.
The ultrasonic transceiver element 1 is rotated and scanned in the directions of arrows A and B via a pulse motor 10, and the propagation time and intensity of the reflected signal between the objects to be measured are measured while stepping the ultrasonic transceiver element 1 at a predetermined angle. is being detected. FIG. 4 is a plot of the reflected signal intensity from the object to be measured 13 when the ultrasonic transmitting/receiving element 1 is rotated and scanned, with the rotation angle of the ultrasonic transmitting/receiving element being plotted on the horizontal axis and the reflected signal intensity being plotted on the vertical axis. This is what I did. 4
6, 47 and 48 are the sides 14 and 1 of the object to be measured 13, respectively.
5.16 are organized, and each side 14, 15, .
16 directions are detected. Furthermore, since the distance to each side of the object to be measured can be obtained from the propagation time of the reflected signal mentioned above, the coordinates of each side 14, 15, 16 of the object to be measured 13 can be determined, and the position of the object to be measured 13 can be determined. can be detected.

However, when a conventional shape detection device is applied to detect the position of a hole, it is possible to detect the position of a large diameter hole;
In a small diameter hole, reflected signals from each side of the hole are superimposed, so there is a problem that position detection cannot be performed unless the attenuation of the ultrasonic wave transmitting/receiving element is significantly improved. Furthermore, when detecting the position of a large-diameter hole using the conventional method, it is necessary to rotate and scan the ultrasonic transceiver element 1 in two axes, which is a big problem in high-speed position detection of a large-diameter hole. It was a dot.

OBJECTS OF THE INVENTION It is an object of the present invention to overcome the above-mentioned drawbacks and provide a position detection method for detecting the position of a small diameter hole at high speed.

Structure of the Invention The present invention is directed to the minimum reflected signal intensity obtained by transmitting and receiving ultrasonic waves by the ultrasonic transmitting/receiving element by changing the relative positional relationship between the ultrasonic transmitting/receiving element and the object to be measured within a predetermined range. The step of detecting the center position of the object to be measured in one axial direction by detecting the value and comparing this minimum value with the reflected signal intensity including the intensity of the reflected signal from the center position of the object to be measured stored in advance. detecting a virtual center position of the other axial direction of the object to be measured using A method for detecting the position of the object to be measured at high speed is obtained by detecting the center position of the object.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 is a system diagram schematically showing a position detecting device for an object to be measured in an embodiment of the present invention. 6 in Figure 5
0 is a means (hereinafter referred to as a manipulator) for changing the relative positional relationship between the object to be measured and the ultrasonic wave transmitting/receiving element 63 (hereinafter referred to as the ultrasonic transducer), and the operation is controlled via the manipulator control device 52. There is. Also the 6th
As shown in the figure, the ultrasonic transducer 53 is installed on the manipulator 50.

The ultrasonic transducer 53 transmits ultrasonic waves of a predetermined frequency toward the target object 27 using an oscillator 66, and receives a reflected signal thereof. The received signal output from the ultrasonic transducer 53 passes through the received signal amplifier 6e.
It is converted into a digital value by an analog-to-digital converter 67 (hereinafter referred to as an A/D converter) and stored in a memory 68. Furthermore, a data processing control device 51 is provided, which includes an interface control unit 59 (hereinafter referred to as ICU), a floppy disk drive device 60 (hereinafter referred to as FDD), and a small electronic computer 61 (hereinafter referred to as CPU). .). ICU39 is FDDeO and CP TJ
e 1 and is also connected to the aforementioned oscillator 66 and memory 68. FDDeO inputs a program or various conditions for performing position detection using this position detection device. In this data processing control device 61, a manipulator control device 52 outputs a control signal for operating an oscillator 65 and controls the operation of a manipulator 6o.
At the same time, the input data transferred from the memory 68 is preprocessed, and the CPU 51 detects the reflected signal intensity, performs arithmetic processing on the position of the object to be measured, and performs processing on the manipulator according to a program inputted in advance from the FDDeO. The amount of movement of 60 and the center position of the object to be measured are calculated.

Next, the operation of the position detection device configured as described above will be explained. FIG. 6 is a side view of hole position detection in this embodiment.
The distance between the target object 64 and the ultrasonic transducer 63 shown in the figure is 100 ms, and the measured object 65 is on the target object 27.
(hereinafter referred to as a hole) has a diameter of 4N, and the wave transmitting/receiving surface of the ultrasonic transducer 63 faces the target object 27.
The ultrasonic transducer 63 is attached to the target object 27 at 2
A case will be described in which scanning is performed in parallel in the six directions of arrows at steps +Il+I+.

The position detection is carried out according to the procedure of the position detection program shown in the flowchart of FIG. 7, which is pre-introduced from FDDeO. In the flowchart of FIG. 7, first, in step 1, the manipulator 60 is driven via the manipulator control device 52 by a control signal from the data processing control device 61 to move the ultrasonic transducer 63 to the sensing start position. In FIG. e, 62 indicates the center position of the ultrasonic beam transmitted from the ultrasonic transducer 63. Further, 63 indicates the intersection point at the start of sensing, 66 at the completion of sensing, and 66 the intersection point between the center position of the ultrasonic beam and the target object 54 at the completion of sensing, and sensing in the X-axis direction is performed in this section. It will be done. In this example, the sensing section in the X-axis direction is 6I.
III! It is.

In addition, the sensing target section in the Y-axis direction is shown in Figure 4.
In this example, it is 6 pharynges).

Next, in step 2, the oscillator 56 is operated by the control signal from the data processing control device 61, and the ultrasonic transducer 63 transmits ultrasonic waves of a predetermined frequency toward the object to be measured 27, and at the same time, the A/D The converter 67 and the memory 68 are operated to store the reflected signal from the target object 54 in the memory 68. In FIGS. 6a and 6b, 62 indicates the center position of the ultrasonic beam transmitted from the ultrasonic transducer 63. In FIG. 8, a reflected signal stored in the memory 68 is shown. Reference numeral 68 indicates a reflected signal from the target object 27.

Next, in step 3, the reflected signal I stored in the memory 68
It is transferred to the CPU 51 via the CU 69.

The CPU 61 processes the reflected signal 68 from the target object 27 according to a program input from FDDeO in advance.
The reflected signal strength P is detected and stored.

Next, in step 4, if the predetermined number of sensing has not been completed, the manipulator 60 is moved 2+++ m in the six directions of the arrows in the same manner as in the above-mentioned method, and the step 2. Repeat step 3. When the predetermined number of sensing operations (three times in this embodiment) is completed, the process proceeds to Step 6.

In step 6, step 2. The center position of the hole 28 in the X-axis direction is detected based on the reflected signal intensity of the reflected signal 68 from the target object 27 obtained by repeating step 3. FIG. 9 shows the intensity of the reflected signal from the target object 27 when the ultrasonic transducer 53 is parallel scanned in the direction of arrow A, and the horizontal axis represents the amount of parallel scanning of the ultrasonic transducer 63.
The reflected signal strength is plotted on the vertical axis.
The CPU 61 performs interpolation processing using quadratic regression on the reflected signal intensity obtained by parallel scanning according to a program inputted in advance from FDDe□, and calculates the minimum value P1 of the reflected signal intensity and the ultrasonic transducer at this time. 63 parallel scanning amount is detected. In Figure 9, 69 is 2
This is the interpolation processing result using the following regression, and the minimum value P1 of the reflected signal intensity from the apex of the curve 69 is 1100 mV, and the parallel scanning amount of the ultrasonic transducer 63 at this time is 3.
It was 8 sore throat. The center position of the hole 28 in the X-axis direction is located at the sensing start position of the ultrasonic transducer 53 described above.
It can be detected by adding the parallel scanning amount column 3.8 to the coordinates.

The CPU 61 also has a target object 2 as shown in FIG.
Place the ultrasonic transducer 63 in hole 2 for hole 28.
The relationship between the amount of change and the reflected signal strength when the relative positional relationship is changed in a uniaxial direction passing through the center position of hole 28 is programmed in a curved form, and the above-mentioned minimum value P1 is applied to this curve. The virtual center position in the Y-axis direction is detected.

In this embodiment, the minimum value P1 of the reflected signal intensity obtained by the above-mentioned parallel scanning is 1,100 mV, and when this is applied to FIG. 10, the relative positional deviation between the hole 28 and the ultrasonic transducer 63 is +3. It can be seen that it is 2nd morning and -3.2nd throat. That is, as shown in FIG. 11, the center position of the hole 28 is such that the X coordinate is the center position of the hole 28 in the X-axis direction and the Y
It can be seen that the coordinates are either position 01 in the +3.2 column or position o2 at -3.2 mm with respect to the Y coordinate of the sensing start position of the ultrasonic transducer 53 mentioned above. 70 indicates the center position of the hole 28 in the X-axis direction.

Next, in step 6, the true hole 28 is located among the virtual center positions o1, 02 of the hole 28 in the Y-axis direction obtained in step 6.
The virtual center position in the Y-axis direction is detected. As mentioned above, the relationship between the sensing position of the ultrasonic transducer 63 in the X-axis direction and the sensing target section (x, y axes) is as shown in FIG. It was easily detected that the position was 01.

In this embodiment, the ultrasonic transducer 63 is inserted into the hole 28.
X along the limit position in the Y-axis direction of the sensing target section of
The center position of the hole 28 was detected by scanning in the axial direction, but
Even if the Y-axis position during scanning in the X-axis direction is set outside the sensing target section, the center position of the hole 28 can be detected using the method of this embodiment.

As described above, according to this embodiment, the reflected signal intensity is obtained by transmitting and receiving ultrasonic waves to and from the workpiece 27 having the hole 28, and simultaneously scanning the ultrasonic transducer 63 in parallel to the workpiece 27. The center position of the hole 28 in the X-axis direction is detected by performing interpolation processing to detect the minimum value P1, and then move the ultrasonic transducer 53 relative to the hole 28 of the workpiece 270 in the uniaxial direction. By comparing the reflected signal intensity and the minimum value P1 when changing the positional relationship, the virtual center position 01. of the two points in the Y-axis direction of the hole 28 is determined. By detecting o2 and further determining whether or not it exists within the sensing target section, the center position of the hole 28 can be detected, and in this example, a position accuracy of 0.2 degrees was obtained. The number of times of sensing to detect the position of the hole 28 in the sensing section (6 ends for both x and y axes) is 3 times, which is significantly reduced compared to the conventional example, and the hole position can be detected at high speed. Ta.

Effects of the Invention As described above, the present invention transmits and receives ultrasonic waves to and from an object to be measured, and at the same time changes the relative positional relationship between the ultrasonic wave transmitting/receiving means and the object to be measured within a predetermined range. A reflected signal when the relative positional relationship between the object to be measured and the ultrasonic wave transmitting/receiving element is changed by detecting the center position of the object to be measured in one axial direction from the minimum value of the signal intensity and storing this in advance. The virtual center position of the other axial direction of the object to be measured is detected by comparing the intensities, and further the virtual center position within the predetermined range is detected as the center position of the other axial direction of the tapped hole. Since a method for detecting the center position of a large screw is obtained, its practical effects are great.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing the general configuration of a conventional object shape detection device, Fig. 2 is a perspective view of the conventional device, Fig. 3 is a diagram showing operating waveforms of the conventional device, and Fig. 4 1 is a diagram arranging the operating waveforms of a conventional device, 1 is a side view of the same device, 7 is a flowchart showing an example of a program for hole position detection, and 8 is a diagram illustrating the operating waveforms of a hole position detecting device. Figure 9 is a diagram showing operation waveforms and interpolation processing results, Figure 10 is a diagram showing operation waveforms and interpolation processing results.
The figure shows the relationship between the amount of change and the reflected signal intensity when the relative position of the ultrasonic transceiver element to the hole is changed in one axis direction. Figure 11 is an explanation of the method for detecting the center position of the hole in the Y-axis direction. It is a diagram. 63... Ultrasonic transducer, 28...
...hole, 50...manipulator. Name of agent: Patent attorney Toshio Nakao and 1 other person @1
Figure 3 Figure 4, Il! ￥ Sound) Voice (K Uke Nephew 1 Utami's Old Insertion Warehouse (Fake)
Fig. 5 Fig. 6 Fig. 7 Fig. 8 R Fig. 9 Beta tube erosion

Claims (1)

[Claims] a first step of storing in advance reflected signal intensities including reflected signal intensities from the center position of the object to be measured when the relative positional relationship between the ultrasonic transceiver and the object to be measured is changed; A reflected signal from the object to be measured obtained by transmitting and receiving ultrasonic waves by the ultrasonic wave transmitting and receiving element with the beam center of the ultrasonic wave transmitting and receiving element aligned with the limit position of the detection target range or outside the detection target range. a second step of detecting the center position of the object to be measured in one axial direction by detecting an extreme minimum value of intensity; and a minimum value of the reflected signal intensity of the first step and the reflected signal intensity of the second step. a third step of detecting the virtual center position of the other axial direction of the object to be measured by comparing the two; and a third step of detecting the virtual center position of the object in the other axial direction; A method for detecting the position of an object to be measured, comprising a fourth step of detecting the center position of the other axial direction of the object to be measured.