JP3230549B2 - Method and apparatus for detecting tilt angle of device under test - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting an inclination angle of an object to be measured by precisely measuring an inclination angle of the object to be measured by laser light.

[0002]

2. Description of the Related Art As a conventional tilt angle detecting method of this kind, there is one disclosed in Japanese Patent Application Laid-Open No. 3-29806. FIG. 5 is a configuration diagram for explaining the tilt angle detection method.
The laser beams emitted from the red laser light source 100 and the green laser light source 102 are respectively transmitted through the rotating ground glass 104 and the lenses 106 and 108 to be measured.
A speckle pattern 112 is formed on 10. The speckle pattern 112 is imaged by the camera 114, and the two-dimensional correlation of the image data is obtained to obtain the inclination angle and the like of the DUT 110.

[0003]

However, such a conventional tilt angle detection method requires two laser light sources, a camera, and the like, and furthermore, the processing of image data is complicated. Was inviting.

[0004]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a tilt angle measuring method and a tilt angle measuring method capable of obtaining a tilt angle of an object to be measured with high accuracy by a simple configuration and simple data processing.

[0005]

In order to achieve the above object, a tilt angle measuring method according to the present invention comprises a rotating plate set to face a target and a center of the rotating plate on the rotating plate. A laser light source which is provided at a predetermined distance from the unit and outputs a laser beam modulated at a predetermined timing, and the reflected light from the target object changes in accordance with a change in the position of the laser light source which changes with the rotation of the rotating plate. And calculates the distance to the reflection point on the target, and calculates the length of the elliptical light trace of the laser light drawn on the target by using the maximum value and the minimum value of the distance data to the target. Find the axis,
The tilt angle of the target is calculated based on the position data of the major axis of the elliptical light trace and the distance data between the point and the rotating plate.

Further, the tilt angle measuring device according to the present invention includes the rotating plate, the laser light source, and a light receiving element for receiving a reflected laser beam from the target, and the reflected light received by the light receiving element is provided. A distance calculation circuit for sequentially calculating a distance to a reflection point on the target object based on a phase shift between the laser light and the laser light output from the laser light source in accordance with a change in the position of the laser light source; A memory for storing the numerical value calculated by the distance calculation circuit in correspondence with the rotational position of the laser light source, and a maximum value and a minimum value of the distance data to the target stored in the memory. To determine the major axis of the elliptical light trace of the laser light drawn on the target, and based on the position data of the major axis of the elliptical light trace and the distance data between the point and the rotary plate at that point. Was that a tilt angle calculation circuit for calculating the inclination angle.

In this device, the light receiving element may be provided at a rotation center position on the rotating plate, or the rotating plate may be formed of an annular disk, and the rotating plate may be provided on the rear side thereof. The laser light source is provided on the rotation center axis of the rotating plate, and a first reflecting mirror is installed on the target side on the rotation center axis of the rotating plate, and reflected laser light from the first reflecting mirror is provided. May be provided on the rotating plate, and the first reflecting mirror may be integrally provided on the rotating plate.

[0008]

When a laser beam is output from a laser light source toward a target and a rotating plate provided with the laser light is rotated, an elliptical light trace corresponding to the inclination of the target is drawn on the plane of the target. On the other hand, the reflected light from the target is received, and the distance from the laser light source to each reflection point of the elliptical light trace is calculated. The line connecting the reflection points corresponding to the maximum value and the minimum value of these distance data is the major axis of the elliptical light trace. The short axis orthogonal to the long axis is an axis perpendicular to the laser light. Therefore, the angle of the long axis with respect to the laser light is equal to the inclination of the target with respect to the laser light. Further, the direction of the inclination of the target with respect to the laser beam can be calculated from the position data of the long axis and the short axis. This is clear from the mathematical theory that the cut surface of a cylinder cut in a plane becomes an ellipse.

[0009]

FIG. 1 is a block diagram showing an embodiment of a tilt angle measuring method and apparatus according to the present invention, and FIG. 2 is an explanatory diagram of the embodiment. Hereinafter, a detailed description will be given based on these drawings.

The tilt angle measuring apparatus 10 is provided with a rotating plate 14 set facing the target 12 and is mounted on the rotating plate 14 at a predetermined distance from the center of the rotating plate 14 and is modulated at a predetermined timing. Laser light source 1 that outputs laser light Lf
6 and a light receiving element 18 for receiving the reflected laser light Lr from the target 12. The reflected laser light Lr received by the light receiving element 18 and the laser light L output from the laser light source 16 are provided.
a distance calculation circuit 20 for sequentially calculating the distance to the reflection point P on the target 12 based on the phase shift with respect to f in accordance with a change in the position of the laser light source 16. A memory 22 for storing the numerical values corresponding to the rotational position of the laser light source 16, and drawing on the target based on the maximum and minimum values of the distance data to the target 12 stored in the memory 22. The major axis 28 of the elliptical light trace 24 of the obtained laser light Lf is determined, and the elliptical light trace 24 is obtained.
Data of the long axis 28 of the rotary table and the rotating plate 1 at that point
And a tilt angle calculating circuit 30 for calculating the tilt angle of the target 12 based on the distance data between the target and the target.
Further, the light receiving element 18 is provided at a rotation center position on the rotating plate 14.

The rotary plate 14 is rotated by a motor (not shown) or the like, and the laser light source 16 moves like a locus 32. The rotation position of the laser light source 16 for each constant rotation angle θ of the rotating plate 14 is represented by θn. When the laser light Lf is output from the laser light source 16 toward the target 12 at the rotational position θ0, the laser light Lf is scattered on the target 12 and a part thereof is received by the light receiving element 18 as reflected laser light Lr. You. Rotation position θ
The distance D0 to the reflection point P0 at 0 is stored in the memory 22 via the distance calculation circuit 20. Subsequently, when the laser light source 16 reaches the rotation position θ1, the above operation is repeated again, and the distance D to the reflection point P1 at the rotation position θ1 is changed.
1 is stored in the memory 22. Thus, the distance data D0, D1, D2,.
Is obtained.

The maximum value Dmax of these distance data is
The straight line connecting the reflection points Pmax and Pmin at the minimum value Dmin is the long axis 28. Also, since the minor axis of the ellipse is orthogonal to the major axis, the reflection points Pa and Pb at both ends of the minor axis 26 are respectively intermediate points between the reflection points Pmax and Pmin. For example, a point given by a, b = min ± (max−min) / 2. Here, the angle φ between the laser beam Lf and the major axis 28 is given by the following equation, as shown in FIG. 3, where R is the distance from the rotation center O of the rotating plate 14 to the laser light source 16. φ = tan ⁻¹ (2R / (Dmax−Dmin)) + π / 2 The angle φ is equal to the inclination of the target 12 with respect to the laser light Lf. The long axis 28 is perpendicular to the rotational positions θmax and θmin, and the reflection points Pmax and Dmax are separated by distances Dmax and Dmin, respectively.
Since it is a straight line connecting Pmin, the position can be calculated. Similarly, the position of the short axis 26 can be calculated. Therefore, the major axis 28
The direction of the inclination of the target 12 with respect to the laser beam Lf can also be calculated from the position data of the target and the short axis 26.

FIG. 4 is a block diagram showing another embodiment of the tilt angle measuring device according to the present invention. The illustration and description of the same parts as in FIG. 1 are omitted. In this tilt angle measuring device, the rotating plate 40 is formed of an annular disk, and a laser light source 42 is provided on the rotating center axis of the rotating plate 40 on the back side of the rotating plate 40. The reflecting mirror 44 is installed on the object side, and a reflecting mirror 46 for reflecting the reflected laser beam Lf2 from the reflecting mirror 44 toward the target object is provided on the rotating plate 40, and the reflecting mirror 44 is supported by the rotating plate 40. It is provided integrally with the member 50. Rotating plate 40 and reflecting mirror 4
Reference numeral 4 is rotated by a motor (not shown) or the like. When the laser light Lf1 is output from the laser light source 42 to the reflecting mirror 44, the laser light Lf1 is reflected on the reflecting mirror 44 by 90 °. Then, the reflected laser light Lf2 is reflected again by 90 ° by the reflecting mirror 46, and travels to the target as the laser light Lf3. The reflected laser beam Lr reflected by the target is received by the light receiving element 4
8 is received.

The tilt angle measuring method and the apparatus according to the present invention are applied to the measurement of the tilt angle of the tire with respect to the wheel axis, the angle of a variable angle gutter, the sensor of a robot arm, the inclination of a motorcycle with respect to the ground. Angle measurement and the like.

[0015]

According to the tilt angle measuring method and apparatus according to the present invention, an elliptical light trace is drawn on a target object with a laser beam, and the major axis of the elliptical light trace is obtained. Moreover, the inclination angle of the target can be measured by simple data processing. Therefore, downsizing and simplification of the device can be realized.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing one embodiment of the present invention.

FIG. 3 is an explanatory view showing one embodiment of the present invention.

FIG. 4 is a configuration diagram showing another embodiment of the present invention.

FIG. 5 is a configuration diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Inclination angle measuring device 12 Target 14 Rotating plate 16 Laser light source 18 Light receiving element 20 Distance calculation circuit 24 Elliptical light trace 28 Long axis of elliptical light trace 30 Tilt angle calculation circuit

Claims (4)

(57) [Claims] A rotating plate set to face a target;
A laser light source mounted on the rotary plate at a predetermined distance from the center of the rotary plate and outputting a laser beam modulated at a predetermined timing; and a change in the position of the laser light source that changes with the rotation of the rotary plate. The reflected light from the target is received in accordance with and the distance to the reflection point on the target is calculated, and drawn on the target using the maximum value and the minimum value of the distance data to the target. Calculating the major axis of the elliptical light trace of the obtained laser beam, and calculating the inclination angle of the target based on the position data of the major axis of the elliptical light trace and the distance data between the point and the rotating plate. A method for detecting an inclination angle of an object to be measured, characterized in that: 2. A rotating plate set to face a target,
A laser light source which is provided at a predetermined distance from the center of the rotary plate and outputs laser light modulated at a predetermined timing on the rotary plate, and a light receiving element for receiving reflected laser light from the target is provided. The distance to the reflection point on the target object based on the phase shift between the reflected laser light received by the light receiving element and the laser light output from the laser light source, according to a change in the position of the laser light source. A distance calculating circuit for sequentially calculating, a memory for storing numerical values calculated by the distance calculating circuit corresponding to the rotational position of the laser light source, and a distance data to a target stored in the memory. While obtaining the major axis of the elliptical light trace of the laser light drawn on the target object based on the maximum value and the minimum value of, the position data of the major axis of the elliptical light trace and the rotating plate at that point Inclination angle detection device of the object which is characterized by comprising an inclined angle calculation circuit for calculating the inclination angle of the target based on the distance data between. 3. The apparatus according to claim 2, wherein the light receiving element is provided at a rotation center position on the rotating plate. 4. The rotary plate comprises an annular disk, and the laser light source is mounted on the rotation center axis of the rotation plate on the back side of the rotation plate, and the target on the rotation center axis of the rotation plate is provided. A first reflecting mirror is installed on the rotating plate, and a second reflecting mirror that reflects the reflected laser light from the first reflecting mirror toward the target object is provided on the rotating plate. 3. The device for detecting the tilt angle of an object to be measured according to claim 2, wherein one reflecting mirror is integrally provided on the rotating plate.