JPH07286845A - Method and instrument for measuring three-dimensional shape - Google Patents

Abstract

PURPOSE:To precisely the measure three-dimensional shape by reducing the occurrence of measurement error resulting from the inclination, etc., of a surface to be measured. CONSTITUTION:The angle at a measuring point is determined from the reflected waves of an ultrasonic beam and, at the same time, the position of the measuring point is measured by using the reflected light of a light beam. At the time of scanning the angle at the measuring point with angle scanning devices 3 and 4 which scan the angle at the measuring point by moving both heads 1 and 2 on a spherical surface around the measuring point by providing an angle detecting head 1, a position measuring head 2 which measures the position of the measuring point by transmitting and receiving a laser beam, and the angle scanning devices 3 and 4, the position of the measuring point is detected and measured by means of the head 2 from the angle detected and measured results of the head 1. Position scanning devices 6, 7, and 8 which move the measuring point of the object 5 and an arithmetic processor 11 which calculates and outputs three-dimensional shape signal based on the moving position information of the measuring point from the devices 6, 7, and 8 and position detecting and measuring information of the head 2 from the angle detected and measured results at the measuring point obtained by the head 1, are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional shape measuring method and apparatus.

[0002]

2. Description of the Related Art Conventionally, in order to measure a three-dimensional shape by an optical non-contact method, the spot position of reflected light is measured by a triangulation method.
There is known a system of measuring displacement by detecting with an optical position detector such as SD or CCD.

As shown in FIG. 8, the displacement z of the reflection surface S causes the reflection spot to move on the optical position detector. Therefore, it is the principle of trigonometry to detect this a and measure the change z. is there. In this case, since the light projecting system and the light receiving system form a biaxial optical system, the influence of the tilt direction and shape of the reflecting surface S becomes large, and this has the drawback of appearing as a measurement error. That is, for example, as shown in FIG. 9, when the measurement surface has an inclined S ₁ surface and a horizontal surface S ₂ , when the irradiation beam l ₀ hits the point P _{1 of the} slope S ₁ , the reflected light l ₁ is
It is detected at the a ₁ position of the line sensor, but at this time P ₁
Light l ₂ of the reflected light at the point were secondary reflection strikes the horizontal surface S ₂
Is strongly detected at the a ₂ position of the sensor. Therefore, the light spot position on the sensor at this time is detected and processed so as to be at the intermediate position between a ₁ and a ₂ , and the point a
A position deviated from ₁ will be detected.

[0004]

DISCLOSURE OF THE INVENTION The present invention reduces the influence of the inclination of the measurement surface in the above-mentioned shape measurement,
The purpose is to enable precise measurement with less measurement error.

[0005]

A tilt angle of a measuring point is determined by a reflected wave of an ultrasonic beam, and a position of the measuring point is measured by a reflected wave of a light beam.

An angle detecting head for transmitting and receiving an ultrasonic beam, a position measuring head for transmitting and receiving a laser beam, and an angle scanning device for scanning both of the heads on a spherical surface centered on a measurement point of the object to be measured. In the angle scanning by the angle scanning device, the position detection head performs the position detection measurement only when it is within a certain range from the detection determination result of the inclination angle by the angle detection head of the measurement point. It is characterized by doing so.

Further, in the above-mentioned device, the position scanning device for moving the measurement point of the object to be measured and the inclination angle detection judgment result by the angle detection head of the measurement point indicate that it is within a certain range. An arithmetic processing unit for arithmetically outputting a three-dimensional shape signal based on the movement position information of the measuring point by the position scanning device and the position detection and measurement information by the position measuring head is provided only at a certain time.

[0008]

As described above, according to the present invention, the tilt angle of the measuring point is determined by the reflected wave of the ultrasonic beam, and the position of the measuring point is measured by the reflected wave of the light beam. The inclination angle of the measurement point can be determined with high precision by utilizing the high angle characteristic of the wave, that is, the directional characteristic, and the angle range in which the light beam strikes the measurement surface almost perpendicularly based on this determination result. It is possible to determine the position of the measurement point only when there is, and it is possible to reduce the measurement error due to irregular reflection of light and improve the measurement accuracy. Since the position measurement uses a light beam such as a laser, it can be easily focused on a minute spot, and by eliminating the scattered light, the position (distance) can be measured with high accuracy.

Further, according to the present invention, an angle scanning device for scanning the angle detecting head and the position measuring head on a spherical surface centering on the measuring point of the object to be measured is provided, and in the angle scanning by the angle scanning device, the measuring point is measured. From the determination result of the inclination angle detected by the angle detection head, the position measurement head is used to detect and measure the position only when it is within a certain range. On the other hand, the position can always be measured in a fixed angle range, that is, in a substantially vertical direction so as to face each other, and precise measurement can be performed.

Further, according to the present invention, the position scanning device for moving the measuring point of the object to be measured and the inclination angle detection judgment result of the angle detecting head for the measuring point indicate that it is within a certain range. Only at the time, an arithmetic processing unit that arithmetically outputs a three-dimensional shape signal is provided based on the moving position information of the measurement point by the position scanning device and the position detection measurement information by the position measuring head. The effect that measurement can be performed automatically is obtained.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment of the drawings. In FIG. 1, reference numeral 1 denotes an angle detection head based on a reflected wave of an ultrasonic wave beam, which is composed of a sensor that focuses the ultrasonic wave beam by a concave vibrator, irradiates a measurement surface with improved directional characteristics, and receives the reflected wave. . Reference numeral 2 denotes a position measuring head based on a reflected wave of a laser beam, which is an irradiation system of a semiconductor laser 21 and a lens 22 and a line sensor 2 as shown in FIG.
A light receiving system for the lens 3 and the lens 24 is provided on two axes l ₀ and l ₁ having a required angle.

Reference numeral 3 denotes an arm for supporting both the heads 1 and 2, which is rotated by a motor 4 about a base point of the arm to rotate an arc centering the both heads 1 and 2 at an irradiation point. Then, an angle scanning device for moving the heads 1 and 2 on a spherical surface centered on the measurement point of the object to be measured is constructed. An object to be measured 5 is fixed to the x and y drive table 6, and a measuring position scanning device for moving the measuring point of the object to be measured is constituted by the x-axis drive motor 7 and the y-axis drive motor 8. 9 is a drive motor for controlling the vertical z-axis position of the table,
Reference numeral 10 is an NC control device for automatically controlling each of the motors 4, 7, 8 and 9.

Reference numeral 11 denotes an arithmetic processing unit, which is an NC control unit 10.
Is supplied from the angle detection head 1 and the position measurement head 2 as calculation information, and from the measurement result by detecting the inclination angle of the measurement point, it is within a certain range. Only at this time, the three-dimensional shape signal is calculated and output based on the moving position information of the measuring point and the position measuring information of the measuring head 2. A printer 12 prints out the arithmetic output of the arithmetic unit 11 on a tape or the like.

In the above, the ultrasonic wave emitted from the angle detecting head 1 is, for example, a pulse of 500 kHz, and the distance to the measuring point P, that is, the set distance is, for example, 150 to 20.
When the motor 9 is set to about 0 mm, the spot radius can be narrowed to r = 2 to 2.5 mm according to the characteristic diagram of FIG. Further, FIG. 4 shows the angle characteristic, and the detection angle of the reflected wave is about 4 ° to 3 ° at the set distance of 150 to 200 mm. That is, as described with reference to FIG. 5, if the tilt angle θ of the irradiation point P is within 4 °, the reflected wave from the point P can be detected, but if it is 4 ° or more, it cannot be detected. The detection signal of the head 1 is supplied to the arithmetic processing unit 11, and if it is below a predetermined value by the discrimination of the signal, P
If the inclination angle θ of the point is 4 ° or more and the detection signal is a predetermined value or more, it is determined that the angle θ is within 4 °.

The determination result of the arithmetic processing unit 11 is θ> 4.
If the angle is °, a signal is applied from the device 11 to the NC device 10, and the motor 4 is driven to cause the heads 1 and 2 to perform circular arc rotation around the measurement point P, while θ> 4 °. Controls the irradiation angle of ultrasonic waves. When the result of the signal discrimination of the detection head 1 is θ <4 ° is discriminated by the angle control by this rotation, at this time, it is confirmed that the irradiation angle of the ultrasonic beam for irradiating point P is almost perpendicular to the surface. It was decided, and at this time, from the device 11 to the NC device 1
A rotation stop signal is sent to 0 to stop the rotation of the motor 4.

By the above angle control, the head 1 is fixed at a position where the facing irradiation direction of the point P is substantially vertical, and at this time, the laser position measuring head 2 is also facing substantially perpendicular to the point P. , The laser beam l ₀ of the oscillator 21 of FIG.
Is almost perpendicular to the measurement point P on the surface S, and its reflected wave is detected on the line sensor 23 through the lens 24.
As described with reference to FIG. 8, the displacement z of the reflection surface S moves the light spot position a of the line sensor 23, and the displacement a can be measured by detecting the position a by the principle of the triangulation method. That is, the arithmetic processing unit 11 A-D converts the detection signal of the line sensor 23 and inputs it, and the digital signal is subjected to data processing such as linear correction and averaging by a plurality of CPUs. The data-processed measurement result is temporarily stored in memory, and the three-dimensional shape signal is calculated and output together with the position information on the x and y planes of the measurement point P from the NC controller 10.
The printer 12 prints out.

As described above, in the position measurement using the laser beam, only the detection signal from the measuring head 2 when the laser irradiation is performed substantially perpendicular to the point P is performed by the arithmetic processing unit 11.
Since the data is processed by the method, it is possible to perform measurement with extremely high accuracy by reducing the measurement error due to irregular reflection such as secondary and tertiary reflection caused by irradiating the inclined surface with a laser at an acute angle and measuring the position. When the measurement of the measurement point P is completed, the measurement points of the object 5 to be measured are sequentially moved by driving the x-axis motor 7 or the y-axis motor 8 and changed to repeat the measurement operation, and the measurement points of the angle detection head 1 are measured. According to the inclination angle determination of the position, the laser beam is irradiated by the position measuring head 2 when it is facing within a certain range, that is, when the position is almost perpendicular to the measurement surface, and the position detection measurement value using the reflected wave from the measurement point is obtained. It is effective, and this measurement control is performed over the entire surface of the measured object 5, and the three-dimensional shape can be precisely measured by the arithmetic processing of the effective data.

FIG. 6 shows an embodiment of the measurement scanning shape of the upper surface of the object 5 to be measured. The measuring point is started from the Start position, the x-axis is moved leftward as indicated by the arrow, and at the end of the object 5 to be measured. The entire surface is scanned up to the Stop position by repeating this so that the predetermined unit length is moved to the y-axis and turned back, and the x-axis is moved to the right. This scanning is performed by the NC device 10 for the x-axis motor 7
And the y-axis motor 8 is driven, and when the measurement target 5 is moved to the concave portions 51 and 52 and the convex portions 53 and 54 during the scanning, the motor 4 is driven to control the irradiation angle so that the surface of the measurement point is changed. Accuracy is improved by measuring from a vertical angle. Of course, the entire surface of the measured object 5 may be scanned by x, y scanning, the positions of the uneven portions 51 to 54 may be stored in advance, and then only the uneven portions 51 to 54 may be measured while controlling the angle. . The angle scanning device may use a moving device on a spherical surface other than that of the embodiment, and may be configured to rotate the measured object side.
Further, the measuring position scanning device may move the heads 1 and 2 side.

FIG. 7 shows an embodiment for measuring the central symmetrical body 13, 14 is a motor rotating about the axis of symmetry, and 15 is a vertical z-axis.
This is a motor that controls axial movement. The angle detection head 1 and the position measurement head 2 have an arc axis 16 centered on the measured object 13.
Is provided to move. The rotary motor 14 and the z-axis control motor 15 are controlled by the NC control device, and once the position of the z-axis is set, the motor 14 rotates to scan one round. Only the measurement signal of the position measuring head 2 when the tilt angle of the measurement surface is within a certain range is processed by the angle detection head 1 at that time as valid data, and those outside the range are excluded, and this scanning measurement is performed. The z-axis motor 15 is controlled by the z-axis motor 15 to repeat the rotational scanning of each z-axis position, and the heads 1 and 2 are moved one step at a time on the circular arc axis 16 to detect and measure the irradiation angle. Then, data processing is performed only for those whose measurement angles are within a certain range, and the three-dimensional shape of the model is measured as a whole.

As described above, the shape measurement signal is printed out on the tape or the like by the printer 12. If the machine tool is driven by using this tape, the model shape can be easily machined by NC control, and the high-precision machining can be performed. Precision measurement results in high precision manufacturing.

[0021]

As described above, according to the present invention, the angle of the measuring point is determined by the reflected wave of the ultrasonic beam, and the position of the measuring point is measured by the reflected wave of the light beam. The angle characteristic of the reflected ultrasonic wave and the high directivity can be used to determine the angle of the measurement point with high accuracy. Based on the result of this determination, the light beam will strike the measurement surface almost perpendicularly. The position of the measurement point can be measured only in the angle range, and the measurement error due to irregular reflection of light can be reduced to improve the measurement accuracy. Since the position measurement uses a light beam such as a laser, it is easy to focus on a minute spot, and scattered light can be eliminated by hitting the measurement surface perpendicularly, and position measurement can be performed with extremely high accuracy. effective.

Further, according to the present invention, an angle scanning device for scanning the angle detection head and the position measuring head on a spherical surface centered on the measurement point of the object to be measured is provided, and in the angle scanning by the angle scanning device, the measurement is performed. From the detection result of the angle detected by the point angle detection head, the position measurement head is used to detect and measure the position only when it is within a certain range. On the other hand, the position of the beam can be always measured in a fixed angle range, that is, in a substantially vertical direction, and the position can be measured, and precise measurement can be performed.

Further, according to the present invention, based on the position scanning device for moving the measuring point of the object to be measured and the detection detection result of the angle by the angle detecting head of the measuring point, it is determined that it is within a certain range. Only, the automatic measurement of the three-dimensional shape is extremely precise because the arithmetic processing unit that arithmetically outputs the three-dimensional shape signal is provided based on the position information of the measuring point by the position scanning device and the position detection measurement information by the position measuring head. There is an effect that can be.

[Brief description of drawings]

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

FIG. 2 is a partial detailed view of FIG.

3 is a spot diameter characteristic diagram of a part of FIG. 1. FIG.

FIG. 4 is an angle characteristic diagram of a part of FIG.

5 is an explanatory diagram of a part of FIG. 1. FIG.

FIG. 6 is a scanning explanatory diagram of FIG. 1.

FIG. 7 is a partial configuration diagram of another embodiment of the present invention.

FIG. 8 is an explanatory diagram of a conventional example.

FIG. 9 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Angle detection head 2 Position measurement head 3 Arm 4 Rotation motor 5 Object to be measured 6 Table 7 x-axis motor 8 y-axis motor 9 z-axis motor 10 NC control device 11 Arithmetic processing device 12 Printer 21 Laser-22 lens 23 Line sensor 24 lenses

Claims (4)

[Claims] 1. A three-dimensional shape measuring method, comprising: determining a tilt angle of a measurement point by a reflected wave of an ultrasonic beam; and measuring the position of the measurement point by a reflected wave of a light beam. 2. The three-dimensional shape measuring method according to claim 1, wherein the position measurement by the reflected wave of the light beam is measured by using the principle of triangulation. 3. An angle detecting head for transmitting and receiving an ultrasonic beam, a position measuring head for transmitting and receiving a laser beam, and an angle scanning device for scanning both of these heads on a spherical surface centered on a measurement point of an object to be measured. In the angle scanning by the angle scanning device, the position detection head performs the position detection measurement only when the angle detection head at the measurement point detects the inclination angle detection result is within a certain range. A three-dimensional shape measuring device characterized in that 4. An angle detecting head for transmitting and receiving an ultrasonic beam, a position measuring head for transmitting and receiving a laser beam, and an angle scanning device for scanning both heads on a spherical surface centered on a measurement point of an object to be measured. In the angle scanning by the angle scanning device, the position detection head performs the position detection measurement only when it is within a certain range based on the inclination angle detection determination result by the angle detection head of the measurement point. In the device, the position scanning device that moves the measurement point of the measured object, and the detection determination result of the tilt angle by the angle detection head of the measurement point, only when it is within a certain range, An arithmetic processing unit for arithmetically outputting a three-dimensional shape signal based on the moving position information of the measurement point by the position scanning device and the position detection measurement information by the position measuring head is provided. A three-dimensional shape measuring device characterized in that