JPH0257278B2 - - Google Patents

Description

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

Configuration of conventional example and its problems A conventional device for detecting the shape of a measured object detects the position and orientation of the measured object from the reflected signal intensity obtained by rotating and scanning an ultrasonic wave transmitting/receiving element with respect to the measured object. There is something that detects 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 shape 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 signals from 5 and 16 reach the ultrasonic transceiver element 1, are amplified by the received signal amplifier 3, are analog-to-digital converted, and are stored in the memory 15. FIG. 3 shows the operating waveforms of the ultrasonic transceiver element 1 stored in the memory 15.
8 and 39 are the sides 14 and 1 of the target object 13, respectively.
5 and 16 are shown. The reflected signals stored in the memory 15 are transferred to the small computer 6, and the transmission times 40, 41, 42 and the reflected signal strength 4 of the reflected signals 37, 38, 39 shown in FIG.
3, 44, and 45 are detected.

In addition, in FIG. 2, the ultrasonic transmitting/receiving element 1 is configured to rotate and scan in the directions of arrows A and B via a pulse motor driver 11 and a pulse motor 10 in response to a control signal from a small electronic computer 6. While stepping the wave transmitting/receiving element 1 at a predetermined angle, the transmission time and intensity of the reflected signal between the objects to be measured are detected. Fig. 4 plots the intensity of the reflected signal 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 on the horizontal axis and the reflected signal intensity on the vertical axis. This is what I did. 46, 47, and 48 are organized reflection signals from each side 14, 15, and 16 of the object to be measured 13, and are rotational scans of the ultrasonic transceiver element 1 when the intensity of each reflection signal is maximum. The direction of each side 14, 15, 16 of the object to be measured 13 is detected from the angle. Furthermore, since the distance to each side of the object to be measured can be obtained from the transmission time of the reflected signal described above, the coordinates of each side 13, 14, 15 of the object to be measured 13 can be determined, and the position of the object to be measured 13 and Posture can be detected.

However, conventional position and orientation detection devices cannot be
When applied to groove shape detection, it is possible to detect the shape of large diameter holes or wide grooves, but in small diameter holes or narrow width grooves, reflected signals from each side of the hole or groove are superimposed, and ultrasonic waves are detected. There was a problem in that the shape could not be detected unless the attenuation of the wave transmitting and receiving elements was significantly improved.

The present inventors have already proposed a shape detection device for an object to be measured in order to solve the above-mentioned conventional problems.

FIG. 5 is a system diagram of an apparatus for detecting the shape of an object to be measured, which has already been proposed by the present inventors. Further, FIG. 6 is a perspective view when the present shape detection device is applied to detect the position of the hole 82. FIG. 7 is a plan view of the same. In FIG. 7, the ultrasonic wave transmitting/receiving element 73 is attached to the manipulator 72 so as to face the target object 81 at an angle of θ, and is moved in parallel in the X-axis direction. In FIG. 6, reference numeral 83 indicates the center position of the ultrasonic beam transmitted from the ultrasonic wave transmitting/receiving element 73, and the ultrasonic wave transmitting/receiving element 73 moves from the scanning start position 84 to the scanning end position 85 at constant distance intervals. It moves while transmitting and receiving waves. FIG. 8 shows the intensity of the reflected signal from the target object 81 when the ultrasonic transmitting/receiving element 73 is scanned in parallel in the X-axis direction, the horizontal axis is the parallel scanning amount of the ultrasonic transmitting/receiving element 73, and the vertical axis is the reflected signal intensity. This is a plot taken from . Here, by detecting the amount of parallel scanning of the ultrasonic wave transmitting/receiving element 73 when the reflected signal intensity takes a minimum value, and adding the parallel scanning amount to the coordinates of the scanning start position 84 of the ultrasonic wave transmitting/receiving element 73, The center position of the hole 82 on the top can be detected. Also, the hole 82 on the Y axis
The center position of can also be detected in the same way.

On the other hand, the hole 82 is
When detecting the position of the hole 82, the accuracy of position detection of the hole 82 is determined by the detection sensitivity S, so it is desired to achieve high position detection accuracy by increasing the detection sensitivity.

Purpose of the Invention The present inventors have made extensive studies on increasing the detection sensitivity of a device for detecting the shape of an object to be measured using an ultrasonic transceiver element, and have determined the angle of inclination between the ultrasonic transceiver element and the central axis of the object to be measured. It was discovered that all of the above problems could be solved by finding an appropriate value for , and the present invention was developed.

That is, it is an object of the present invention to eliminate the above-mentioned drawbacks and to provide an apparatus capable of highly accurate position detection of an object to be measured with a simple configuration.

Composition of the Invention The present invention processes the reflected signal intensity from the object to be measured, which is obtained by scanning the object to be measured with an ultrasonic beam transmitted from an ultrasonic transceiver element. In a device for detecting the position of a measured object having a signal processing means for detecting the shape of the object,
The wavelength of the ultrasonic wave transmitted and received by the ultrasonic wave transmitting/receiving element is λ, the diameter of the ultrasonic wave transmitting/receiving element is D, θ=
When sin1.22λ/D (rad), the axis perpendicular to the beam transmission surface of the ultrasonic wave transmitting/receiving element is θ The object of the present invention is to obtain a device which is configured to be tilted almost equally as shown in FIG.

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

The schematic system diagram of the hole position detection device according to the first embodiment of the present invention is the same as that shown in FIG. 5 described above, and its configuration will be described below.

In FIG. 5, 72 is a means (hereinafter referred to as a manipulator) for changing the relative positional relationship between the object to be measured and an ultrasonic wave transmitting/receiving element (hereinafter referred to as an ultrasonic transducer), and is controlled by a control signal from the data processing control device 70. The operation is controlled via a manipulator control device 71. Further, on the manipulator 72, an ultrasonic transducer 73 for both transmitting and receiving waves is installed.

The ultrasonic transducer 73 uses an oscillator 80 to transmit ultrasonic waves of a predetermined frequency toward a target object, and receives a reflected signal thereof. The received signal output from the ultrasonic transducer 73 passes through a received signal amplifier 74, is converted into a digital value by an analog-to-digital converter 75 (hereinafter referred to as an A/D converter), and is stored in a memory 76. be done.
Furthermore, a data processing control device 70 is provided,
This data processing control device 70 is composed of an interface control unit 77 (hereinafter referred to as ICU), a floppy disk drive device 78 (hereinafter referred to as FDD), and a small electronic computer 79 (hereinafter referred to as CPU). The ICU 77 is connected to the FDD 78 and the CPU 79, as well as to the aforementioned oscillator 80 and memory 76. FDD78
inputs a program or various conditions for performing position detection using this position detection device. This data processing control device 70 outputs a control signal for operating an oscillator 80, and a manipulator 7
Manipulator control device 71 that controls the operation of 2
It also outputs control signals to the memory 76.
pre-processes the input data transferred from
According to the program stored in advance from the FDD 78, the CPU 79 detects the intensity of the reflected signal, performs arithmetic processing on the position of the hole in the target object, and performs the manipulator 72.
The amount of movement is calculated.

Next, the operation of the position detection device configured as described above will be explained. Note that in this embodiment, FIGS. 6 and 7
The diameter of the ultrasonic transducer 73 shown in the figure is 36
mm, the driving frequency is 66 KHz (wavelength λ = 5.14 mm), the distance between the target object 81 and the ultrasonic transducer 73 is 100 mm, and the diameter of the hole 82 in the target object 81 is 5 mm.
The transmitting and receiving wave surface of the ultrasonic transducer 73 is set at a predetermined angle θ (10° in this embodiment) with respect to the target object 81.
It is arranged at an angle, and the X
A case will be described in which parallel scanning is performed in the axial direction while maintaining a constant distance from the target object 81.

Position detection is performed according to the procedure of the position detection program shown in the flowchart of FIG. 9, which is input and stored in advance from the FDD 78. In the flowchart of FIG. 9, first, in step 1, the manipulator 72 is driven via the manipulator control device 71 in response to a control signal from the data processing control device 70 to move the ultrasonic transducer 73 to the sensing start position 84. In FIG. 6, 83 indicates the center position of the ultrasonic beam transmitted from the ultrasonic transducer 73. Further, 84 indicates the intersection point between the center position of the ultrasonic beam and the target object 81 at the time of starting sensing, and 85 at the time of completing sensing, and sensing in the X-axis direction is performed within this section. In this example, the sensing section is 40mm.
It is.

Next, in step 2, the oscillator 80 is operated by the control signal from the data processing control device 70, and the ultrasonic transducer 73 transmits ultrasonic waves of a predetermined frequency toward the object to be measured 81, and at the same time converts the A/D. By operating the device 75 and the memory 76, the target object 8 is
The reflected signal from 1 is stored in memory 76. 1st
FIG. 0 shows the reflected signal stored in the memory 76. Reference numeral 90 indicates a reflected signal from the target object 81.

Next, in step 3, the reflected signal stored in the memory 76 is transferred to the CPU 79 via the ICU 77.
The CPU 79 detects the reflected signal intensity P ₁ of the reflected signal 90 from the target object 81 according to a program input and stored in advance from the FDD 78 .

Next, in step 4, the manipulator 72 is moved in the X-axis direction by 0.1 mm, and steps 2 and 3 are repeated, and when a predetermined number of sensing operations (400 times in this embodiment) is completed, the process proceeds to step 5.

In step 5, the above steps 2 and 3 are performed.
The center position of the detection target hole 82 is detected based on the intensity of the reflected signal from the target object 81 including the detection target hole 82 obtained in . Figure 11 shows the target object when the ultrasonic transducer 73 with a diameter of 36 mm and a driving frequency of 66 KHz (wavelength λ = 5.14 mm) is tilted at θ = 10 degrees with respect to the target object and scanned in parallel to the X-axis direction. The reflected signal intensity from 81 is plotted every 10 points, with the horizontal axis representing the parallel scanning amount of the ultrasonic transducer 73 and the vertical axis representing the reflected signal intensity.
The CPU 79 detects the minimum value of the reflected signal intensity according to a program input and stored in advance from the FDD 78 to detect the center position of the hole 82 in the X-axis direction. The hole detection sensitivity _S1 at this time was -16 dB. Note that the hole detection sensitivity S is defined as follows.

That is, the minimum value of the reflected signal from the target object 81 is P ₁ , and the maximum value of the reflected signal from the target object 81 is P 1 .
When P ₂ is assumed, the detection sensitivity S (dB) of the hole 82 is S=20log(P ₁ /P ₂ )(dB) −(1). Further, although a detailed explanation will be omitted, the center position in the Y-axis direction can also be detected in the same manner.

As described above, according to this embodiment, the wave transmitting/receiving surface of the ultrasonic transducer 73 having a diameter of 36 mm is tilted by 10 degrees with respect to the target object 81 having the hole 82 to simultaneously transmit and receive ultrasonic waves with a driving frequency of 66 KHz. The maximum hole detection sensitivity S can be obtained by processing the reflected signal intensity obtained by operating the manipulator 72 and scanning the ultrasonic transducer at a constant distance with respect to the target object 81. This resulted in a hole position detection accuracy of 0.1 mm.

Note that in this embodiment, the ultrasonic transducer 7
The transmitting/receiving wave surface in No. 3 has been described as being inclined at 10 degrees in the scanning direction with respect to the central axis of the hole 82 to be detected, but by changing this angle of inclination, the detection sensitivity of the hole 82 also changes. FIG. 12a shows an ultrasonic transducer 53 having the same configuration as this embodiment.
The target object 5 when the transmitting and receiving wave surface is tilted in the X-axis direction with respect to the central axis of the hole 82 and scanned parallel to the X-axis direction.
4, the horizontal axis is the inclination angle of the ultrasonic transducer 73, and the vertical axis is the detection sensitivity of the hole 82. When the inclination angle θ ₁ is 10 degrees, the detection sensitivity of the hole 82 is showed the maximum value.

Ultrasonic transducer 73 used in this example
The first zero radiation angle θ ₀ is the diameter of the ultrasonic transducer D (mm), the driving frequency f (KHz), and the sound speed C
(mm/S), it can be found from equation 2.

θ ₀ = sin1.22C/f・D(red) −(2) In this embodiment, θ ₀ ≒10° and the ultrasonic transducer 7 when the detection sensitivity of the hole 82 shows the maximum value.
It can be seen that the angle of inclination is almost the same as No. 2.

In addition, FIG. 12b shows a configuration similar to that of this embodiment, with the driving frequency of the ultrasonic transducer 73 set to 51 (KHz).
The reflected signal intensity from the target object 54 is summarized when the transmitting/receiving wave surface is tilted in the X-axis direction with respect to the central axis of the hole 82 and scanned parallel to the X-axis direction, and the tilt angle θ ₁ is 13°. The detection sensitivity of the hole 82 reaches its maximum value when , and the hole detection sensitivity S ₂ at this time is -13 dB.
It was hot. In addition, the first zero radiation angle θ of the ultrasonic transducer 73 at this time is θ ₀ ≒ from the above two equations.
The angle of inclination was 13 degrees, which almost coincided with the inclination angle of the ultrasonic transducer 73 when the detection sensitivity of the hole 82 reached its maximum value.

Effects of the Invention As described above, in the present invention, an ultrasonic wave transmitting/receiving element is arranged such that the axis perpendicular to the beam transmission plane thereof is inclined with respect to the axis perpendicular to the plane on which the ultrasonic beam of the measurement object is scanned. By making the inclination angle approximately equal to the first zero radiation angle of the ultrasonic wave transmitting/receiving element, the maximum detection sensitivity is obtained, so a highly accurate position detecting device can be obtained, and its practical effect is great. There is something.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing the general configuration of a conventional ultrasonic shape detection device, FIG. 2 is a perspective view of shape detection using the conventional device, and FIG. 3 is a diagram showing operating waveforms of the conventional device. Fig. 4 is a diagram arranging the operating waveforms of the conventional device, Fig. 5 is a system diagram showing the general configuration of the device for detecting the shape of a measured object proposed by the present inventors, and Fig. 6 is a diagram showing the same hole. Perspective view of position detection, seventh
FIG. 8 is a diagram arranging the operation waveforms of the device, FIG. 9 is a flowchart showing an example of a program for hole position detection in the first embodiment of the present invention, and FIG. 11 is a diagram showing operation waveforms of the apparatus in the first embodiment of the present invention, and FIG. 12 is a diagram showing hole detection sensitivity in the first embodiment of the present invention. 72...Manpilulator, 73...Ultrasonic transducer, 61...CPU, 82...Hole.

Claims (1)

[Claims] 1. Detecting the shape of the object by processing the intensity of the reflected signal from the object to be measured, which is obtained by scanning the object with an ultrasonic beam transmitted from an ultrasonic transceiver element. λ is the wavelength of the ultrasonic waves transmitted and received by the ultrasonic wave transmitting/receiving element, and D is the diameter of the ultrasonic wave transmitting/receiving element.
When θ=sin1.22λ/D (rad), the ultrasonic transceiver element has an axis perpendicular to its beam transmission surface relative to an axis perpendicular to the surface of the object to be measured over which the ultrasonic beam is scanned. A position detecting device for a measured object, which is arranged to be inclined so as to form an angle of θ.