JPH09159418A - Method and equipment for measuring shape of three-dimensional curved surface molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the shape of a molding having three-dimensional curved surface automatically with high speed and high accuracy by moving the molding between a pair of laser sensors to traverse the laser irradiation axis periodically while varying the traversing position sequentially. SOLUTION: At the time of measuring the shape, W-axis (extending direction of a rotary shaft 30) is set at a position where the blade of a propeller 10 traverses the laser irradiation axis periodically through rotation caused by a first rotary drive system. A second drive system shifts an X-axis table 40 by a predetermined distance in the direction of X-axis at a constant interval so that the locus of laser irradiation to the blade of a propeller 10 describes a partial concentric circle. Laser light reflected from the blade of propeller 10 is subjected to photoelectric conversion through laser sensors 20a, 20b to produce electric signals which are then fed to a control section. Two signals are sampled synchronously and the coordinate of the surface of blade is determined from the sampled values before determining the thickness of blade from the coordinate thus determined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for measuring the shape of a molded product having a three-dimensional curved surface, and particularly to the wall thickness and contour of a molded product such as a propeller for a ship, a propeller for an aircraft or a turbine blade. The present invention relates to a method and an apparatus for measuring the shape of a three-dimensional curved surface molded article suitable for measuring the outer diameter and the like.

[0002]

2. Description of the Related Art A stylus type measuring device is most popular as a shape measuring device for a three-dimensional curved surface molded article. This measuring device usually has measuring needles applied to a plurality of points on the molded product, and measures the wall thickness of the molded product by detecting the position of the stylus of the measuring needle.

[0003]

In the measuring device of this type, when performing a precise measurement, a large number of points are set to measure each designated point, and a few mm above each point.
It is necessary to move the measuring needle to the position of and then gently lower the measuring needle to perform the stylus. By the way, since the time required for 1 point measurement requires 1 second or more, and the moving speed of the measuring needle for the stylus is several (mm / sec),
The time required for measurement increases as the shape of the molded product increases.

Further, in the case of a propeller, an error in the position of the stylus of the measuring needle becomes large at a portion having a large propeller pitch (a portion having a large curvature), which causes a problem when performing highly precise measurement. In addition, in order to measure the contour of the molded product, a contact needle different from the above measuring needle is required.

In view of the above problems, a main object of the present invention is to provide a shape measuring method capable of automatically measuring the shape of a molded product having a three-dimensional curved surface at high speed and with high accuracy. is there.

Another object of the present invention is to provide a shape measuring method capable of simultaneously measuring not only the wall thickness but also the contour and the outer diameter of the molded article.

The present invention further provides a shape measuring apparatus suitable for the above measuring method.

[0008]

According to the present invention, there is provided a method of measuring the shape of a molded article having a three-dimensional curved surface by using a laser sensor for irradiating a laser to measure the distance. The pair of laser sensors are arranged so as to face each other so that their laser irradiation axes are on the same straight line, and the molded product is moved so as to periodically cross the laser irradiation axis between the pair of laser sensors. , A shape of a three-dimensional curved surface molded article, characterized in that measurement values relating to the thickness, the contour, and the outer diameter of the molded article are obtained from the outputs of the pair of laser sensors by moving so as to sequentially change the crossing position. A measurement method can be obtained.

According to the present invention, there is also provided a shape measuring device for measuring the shape of a molded article having a three-dimensional curved surface by using a laser sensor for irradiating the molded article with a laser to measure the distance. A first arrangement in which the laser sensors are arranged to face each other so that their laser irradiation axes are on the same straight line, and the molded product is moved between the pair of laser sensors so as to periodically cross the laser irradiation axis. A drive system, and a second drive system that moves one of the first drive system and one of the pair of laser sensors so that the crossing position sequentially changes,
A control unit that controls the first and second drive systems and that samples output signals from the pair of laser sensors to calculate measured values relating to the thickness, contour, and outer diameter of the molded product. A shape measuring device for a three-dimensional curved surface molded article is obtained.

The first drive system is constituted by a first rotary drive system which has the central axis of the molded product in a position parallel to the laser irradiation axis and apart from the laser irradiation axis. The second drive system drives so that the locus of laser irradiation on the molded product becomes a partial concentric circle.

Further, a third drive system may be provided for moving the pair of laser sensors in the same direction as the laser irradiation axis while keeping the distance between them constant.

Further, the control unit is based on a preset program relating to the outer shape of the molded product,
The third drive system is controlled so that the pair of laser sensors are always within a range in which the distance to the molded product can be measured.

According to the present invention, there is further provided a shape measuring device for measuring the shape of a molded article having a three-dimensional curved surface by using a laser sensor for irradiating the molded article with a laser to measure a distance. A first arrangement in which the laser sensors are arranged to face each other so that their laser irradiation axes are on the same straight line, and the molded product is moved between the pair of laser sensors so as to periodically cross the laser irradiation axis. A drive system, and a second drive system that moves one of the first drive system and one of the pair of laser sensors so that the crossing position sequentially changes,
A rotary drive system for rotating the molded product so that its laser-irradiated surface is perpendicular to the laser irradiation axis;
And a control unit for controlling the second drive system and the rotary drive system, and for sampling output signals from the pair of laser sensors to calculate measured values relating to the thickness, contour, and outer diameter of the molded product. It is possible to obtain a shape measuring device for a three-dimensional curved surface molded article, which is characterized by including.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIGS. here,
The propeller 10 for a ship will be described as a measurement target. In the present invention, a well-known laser sensor is used which irradiates a laser beam onto an object to be measured and receives the reflected light to measure the distance to the irradiation surface. Then, the pair of laser sensors 20a, 20b
Are characterized in that they are vertically opposed to each other so that their laser irradiation axes are on the same straight line. Propeller 10
It is attached to a rotating shaft 30 provided in a position parallel to the laser irradiation axis and apart from the laser irradiation axis so as to be rotatable. The extending direction of the rotating shaft 30 is hereinafter referred to as the W axis. The rotary shaft 30 is driven by a drive motor 32 via a speed reducer 31.
Driven by The rotary shaft 30, the speed reducer 31, and the drive motor 32 may be collectively referred to as a first rotary drive system.

This first rotary drive system is constructed on an X-axis table 40 which is slidable in the left and right horizontal directions in FIG. 1 (hereinafter referred to as the X-axis direction), and is movable in the X-axis direction. . The X-axis table 40 is driven by a ball screw mechanism housed in a box 41 and a servomotor (not shown) for driving the ball screw mechanism. These X-axis table 4
0, ball screw mechanism and servo motor
It may be called the drive system of.

The pair of laser sensors 20a and 20b also has a ball screw mechanism housed in the box 21 and a servomotor (not shown) for driving the ball screw mechanism (neither of which is shown) so that the laser sensor 20a and 20b always maintain a constant interval in the laser irradiation axis direction ( Hereinafter, it will be referred to as the Z-axis direction). These ball screw mechanism and servo motor may be collectively referred to as a third drive system.

In measuring the shape, the W axis is set at a position where the blades of the propeller 10 periodically cross the laser irradiation axis by the rotation of the first rotary drive system. And the second
The drive system is configured so that the locus of laser irradiation on the blades of the propeller 10 becomes a partial concentric circle by moving the X-axis table 40 in the X-axis direction by a constant distance at constant time intervals.

The first rotary drive system and the first and second drive systems are driven by a controller (not shown). The control unit also receives electric signals from the laser sensors 20a and 20b obtained by photoelectrically converting the laser light reflected by the blades of the propeller 10, performs sampling in synchronization with these two electric signals, and outputs a sampling value. Then, the coordinates of the surface of the blade are calculated from the above, and the thickness of the blade is calculated from the difference between them. Speaking of an example of such a calculation method, the laser sensor 20
The distance L between a and 20b is constant, and the laser sensor 20
Laser sensor 20b, distance La from a to the upper surface of the blade
From the sampling value of the distance Lb from the blade to the lower surface of the blade, it is possible to know the coordinates of the upper surface and the lower surface with respect to the Z axis. Therefore, by calculating the difference between them, the wall thickness of the sampled measurement point can be calculated. it can. Of course, the wall thickness T
It can also be calculated by = L- (La + Lb).

FIG. 4 shows an example of the wall thickness measurement points determined by the rotation by the first rotary drive system and the movement in the X-axis direction by the second drive system and the sampling operation as described above. The interval between the measurement points is set to a value of several mm to several tens of mm. In the case of the rotation direction of the propeller 10 shown by the arrow in FIG. 4, the point where the reflected light from the laser sensors 20a and 20b appears and the point where the reflected light disappears are detected as the outline of the blade indicated by the one-dot chain line in the figure. . Further, the outer diameter of the blade is calculated from the detected contour.

Next, the function of the third drive system will be described. The laser sensors 20a and 20b usually have a limited distance measurement range. That is, it is possible to measure the distance from the laser sensor to an object within a predetermined range, and the predetermined range is usually several tens cm. On the other hand, when the propeller for a ship has a diameter of several meters, the difference between the measurement points in the vertical direction becomes several tens cm or more, and the laser sensor 20
If the positions of a and 20b are fixed within the above predetermined range, the laser sensors 20a and 20b may collide with the rotating propeller 10.

Therefore, the outer shape of the propeller 10, that is, an approximate curved surface shape is created in advance by a program and stored in the memory in the control unit. The control unit controls the third drive system based on this program, and the propeller 1
In order to prevent the laser sensors 20a, 20b from colliding with the propeller 10 even if 0 is rotated,
Adjust the position of 20b in the Z-axis direction. Of course, the displacement amounts of the laser sensors 20a and 20b in this case are considered in the calculation of the wall thickness. Here, in the case of the propeller 10, since the upper and lower surfaces of the blade change with the same curvature, that is, have the same curved surface, the movement control of the laser sensors 20a and 20b in the Z-axis direction is performed by the laser sensors 20a and 20b. It is designed to work together with the interval kept constant.

However, in the case of a molded product having curved surfaces whose upper and lower surfaces do not change with the same curvature, the laser sensor 20
One laser sensor may collide with the molded product only by moving it in the Z-axis direction while keeping the distance between a and 20b constant. In consideration of such a case, the laser sensors 20a and 20b may be individually controlled to move. Even in this case, the laser sensors 20a, 20
Since it is possible to know the individual movement amounts of b, it is possible to calculate the wall thickness by performing the calculation in consideration of these movement amounts.

Of course, such a third drive system is not necessary when the difference in the vertical direction of the measurement points in the molded product to be measured is small, that is, in the case of a flat shape. In this case, the laser sensors 20a and 20b have a fixed structure in which the distance between them is constant.

FIG. 5 is a block diagram showing the configuration of the control unit and its peripheral equipment. The control unit 50 receives feedback signals from all the servo motor systems described above and output signals from the laser sensors 20a and 20b, and receives various set values input from the keyboard from the operation panel 51. The control unit 50 also has a storage device such as a hard disk driver or a floppy disk driver,
Receive data such as the above programs through the floppy disk driver. These output signals and data are stored in a built-in memory. The control unit 50 controls the first rotary drive system, the second and third drive systems based on various set values and programs stored in the memory and feedback signals from each servo motor system, and also controls the laser sensor. The wall thickness, contour, and outer diameter of the blades of the propeller 10 are calculated based on the output signals from 20a and 20b. Then, these calculation results are printed out by the printer 52, the plot 53 plots the measurement points and the wall thickness thereof as shown in FIG. 4, and the display 54 displays the calculation results.

A second embodiment will be described with reference to FIGS. 6 and 7 which is applied to a case where the molded product to be measured is a relatively long turbine blade 60. In the case of such a long product, the turbine blade 60 is supported in the horizontal direction by the drive support mechanisms 61a and 61b capable of being rotationally driven. The rotation center axis is the W axis. The drive support mechanisms 61a and 61b are driven by a servo motor drive system (not shown) in a horizontal direction and a direction perpendicular to the W axis (hereinafter,
This is mounted on a table 62 that is movable in the Y-axis direction). Then, the pair of laser sensors 20a, 20b
Is movable along the support column 63 in the laser irradiation axis direction (Z-axis direction) with a constant vertical interval between the measurement points. The column 63 is moved in the horizontal direction and in the X-axis direction perpendicular to the Y-axis by a servo motor drive system (not shown).

Here, the servo motor drive system that drives the table 62 in the Y-axis direction is the first drive system, and the servo motor drive system that drives the support column 63 in the X-axis direction is the second drive system, and the drive support mechanism 61a. , 61b may be referred to as a rotary drive system, and the drive mechanism for driving the laser sensors 20a and 20b in the Z-axis direction may be referred to as a third drive system. In any case, the locus of laser irradiation on the turbine blade 60 by the first, second, and third drive systems is as shown by the alternate long and short dash line in FIG. The rotary drive system is for making the laser irradiation perpendicular to the surface of the turbine blade 60. Therefore, the control of the rotary drive system is performed in synchronization with the position control of the laser irradiation point, that is, the measurement point on the turbine blade 60 by the first drive system. Of course, the third drive system and the rotary drive system are not necessary when the molded product to be measured has a curved surface with a relatively small curvature.

[0027]

As described above, in the shape measuring method and apparatus according to the present invention, the pair of laser sensors are arranged so as to face each other so that their laser irradiation axes are on the same straight line, and the measurement is performed. As a result, the following effects are obtained.

A. The measurement response time of the laser is in the unit of 1/10000 second, and even if the measurement is performed while moving at 100 mm / sec, it is possible to perform measurement at 100 measurement points per 1 mm.

B. By performing position control of a pair of laser sensors with a preset program, it is possible to perform measurements without being restricted by the effective operating range of laser sensors, even for molded products with a large curvature such as a propeller. .

C. The thickness, contour, and outer diameter of a molded product can be measured simultaneously with only a pair of laser sensors.

D. Since it is a non-contact type, it can be applied to a molded product having low rigidity.

E. From the above points, it is possible to easily perform high-speed and highly accurate measurement as compared with the stylus type.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a main part of a first embodiment of a shape measuring apparatus according to the present invention.

FIG. 2 is a plan view of a main part of the shape measuring apparatus shown in FIG.

FIG. 3 is a side view of a main part of the shape measuring device shown in FIG.

FIG. 4 is a diagram showing an example of a distribution of measurement points set for a propeller which is an object to be measured by the shape measuring apparatus of FIG.

5 is a block diagram showing a configuration of a control system of the shape measuring apparatus shown in FIG. 1 and various input / output devices associated therewith.

FIG. 6 is a front view showing a configuration of a main part of a second embodiment of a shape measuring apparatus according to the present invention.

FIG. 7 is a plan view of a main part of the shape measuring apparatus shown in FIG.

8 is a diagram showing an example of a locus of laser irradiation performed on a turbine blade that is an object to be measured by the shape measuring apparatus shown in FIG.

[Explanation of symbols]

 10 Propellers 20a, 20b Laser Sensor 30 Rotating Shaft 31 Reducer 32 Drive Motor 40 X-Axis Table 60 Turbine Blades 61a, 61b Drive Support Mechanism 62 Table

Claims (6)

[Claims] 1. A method for measuring the shape of a molded article using a laser sensor for irradiating a molded article having a three-dimensional curved surface with a laser to measure the distance, the method comprising irradiating a pair of the laser sensors with the laser. Arranged so that the axes are on the same straight line, the molded product is moved so as to periodically traverse the laser irradiation axis between the pair of laser sensors, and the traverse position is sequentially changed. The shape measurement method for a three-dimensional curved surface molded product, characterized in that measurement values relating to the thickness, contour, and outer diameter of the molded product are obtained from the outputs of the pair of laser sensors. 2. A shape measuring device for measuring the shape of a molded article having a three-dimensional curved surface by using a laser sensor for irradiating the molded article with a laser to measure a distance, wherein a pair of the laser sensors are provided. A first drive system that is arranged so as to oppose each other so that the laser irradiation axis is on the same straight line, and that moves the molded product so as to periodically cross the laser irradiation axis between the pair of laser sensors; A second drive system that moves one of the first drive system and one of the pair of laser sensors so that the crossing position sequentially changes, and the pair of lasers while controlling the first and second drive systems. A shape measuring device for a three-dimensional curved surface molded article, comprising: a control unit that samples an output signal from a sensor and calculates measured values relating to the thickness, contour, and outer diameter of the molded article. 3. The shape measuring device according to claim 2,
The first drive system is configured by a first rotary drive system for the molded product, the first rotary drive system having a central axis parallel to the laser irradiation axis and apart from the laser irradiation axis, and the second drive system. Is a device for driving so that the locus of laser irradiation on the molded product becomes a partial concentric circle. 4. The shape measuring apparatus according to claim 2 or 3, further comprising a third drive system that moves the pair of laser sensors in the same direction as the laser irradiation axis while keeping the distance between them constant. A shape measuring device for a three-dimensional molded article, which is characterized by being provided. 5. The shape measuring device according to claim 4,
The control unit controls the third drive system so as to always keep the pair of laser sensors within a range in which the distance to the molded product can be measured based on a preset program relating to the outer shape of the molded product. A shape measuring apparatus for a three-dimensional curved surface molded article, characterized by: 6. A shape measuring device for measuring the shape of a molded article having a three-dimensional curved surface by using a laser sensor for irradiating the molded article with a laser to measure the distance, wherein a pair of the laser sensors are provided. A first drive system that is arranged so as to oppose each other so that the laser irradiation axis is on the same straight line, and that moves the molded product so as to periodically cross the laser irradiation axis between the pair of laser sensors; A second drive system that moves one of the first drive system and one of the pair of laser sensors so that the position where the laser beam crosses is sequentially changed, and the molded product, in which the laser irradiation surface is perpendicular to the laser irradiation axis. A rotational drive system for rotating so as to control the first and second drive systems and the rotational drive system, and sampling the output signals from the pair of laser sensors to obtain the thickness of the molded product, Contour, outside 3, characterized in that a control unit for calculating the measured values for
Shape measuring device for three-dimensional curved surface molded products.