JPH083409B2 - Optical normal scribing detector - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention measures the free-form surface of a three-dimensional solid surface press-molded from, for example, a thin metal plate and obtains a normal line to the surface to be measured at a predetermined position, and scribing at the same time. The present invention relates to an optical normal scribing detector for aligning with a line.

Conventional technology Conventionally, when a free-form surface of a three-dimensional solid surface press-molded from a thin metal plate or the like is measured and a normal line of the surface is obtained, a non-rotatable measurement axis is bent and a bending generated in the measurement axis is measured. By attaching a sensor that measures the pulling force and further attaching a magnet to the tip of this measurement axis, and when the measurement axis is brought closer to the measurement surface during measurement, this magnet is attracted to the measurement surface. A device that calculates the normal error from the magnitude of the output signal of each sensor that is generated, or attach three or more distance measuring sensors to the tip of the non-rotatable measuring axis, and attach it to the surface to be measured during measurement. An apparatus has been used in which a normal line error is calculated from the magnitude of an output signal generated by each sensor when the measurement axes are brought close to each other.

However, in the former device, particularly accurate machining is required to obtain the structure of the measuring axis that can reliably measure the direction and magnitude of the bending force generated on the measuring axis. Due to the characteristics of the magnet attached to the tip, it is impossible to measure in the vicinity of the sharply bent portion of the surface to be measured, the cut groove, the end, or the like. Further, in the latter device, three or more sensors are attached to the tip of the measuring shaft, so the shape of the tip of the measuring shaft becomes large,
Similar to the former device, it is impossible to measure in the vicinity of sharply bent part of the surface to be measured, cutting groove and end part, and moreover, it has a large number of sensors. However, there is a problem that the cost is increased.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to make a rotationally driven portion simple and small, and to measure the surface normal even in the vicinity of a sharply bent portion of the surface to be measured. To do so.

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a means for rotating a compound lens system and outputting a signal corresponding to the rotation phase, so that the surface to be measured imaged by the compound lens system is fixed. By detecting the positional deviation between the detector and the scribe line by imaging the scribe line, and aligning the position, the complex lens system is used to measure the position deviation from the rotation center on the measured surface to the measured surface at a predetermined eccentric amount. By providing an optical distance measuring means for measuring the distance, bringing the measurement axis close to the surface to be measured at the time of measurement, and then rotating the measuring point of the optical distance measurement by rotating the compound lens system, The direction and the magnitude of the normal line error are calculated from the distance measurement signal generated in accordance with the distance and the signal corresponding to the rotation phase.

Configuration of Embodiment Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, an optical normal scribing detection device 1 according to the present invention includes a main body 3 fixed to a frame 2 by, for example, a fastening tool 2a, and a center line A that is substantially perpendicular to a surface S to be measured. A bearing 3a is provided inside the main body 3 so that it can rotate.
And the compound lens frame 4 supported by the bearing 3b. The compound lens frame 4 is provided with a timing pulley 5 for rotational driving at the upper end thereof, and the timing pulley 5 has a timing of a motor 6 as a driving means fixedly arranged outside the main body 3. The timing belt 7 attached to the pulley 6a is wound around. Further, a rotary encoder 8 is connected to the motor 6 as a phase detecting means, and the rotary encoder 8 detects the rotational phase of the motor 6 and outputs a signal to the calculator 9. A compound lens 4c including a convex lens 4a perpendicular to the center line A and a wedge-shaped cylindrical lens 4b around the convex lens 4a is attached to the compound lens frame 4.

Further, on the upper part of the main body 3, a distance detector 10 is attached as an optical distance measuring means. The distance detector 10 has an image receiving surface 11a facing the convex lens 4a on the center line A.
And a cylindrical lens 4 arranged on opposite sides of the optical fiber bundle 11 with the image receiving surface 11a of the optical fiber bundle 11 interposed therebetween.
A light emitting element 12 such as a semiconductor laser is used as an illuminating unit facing b.
And a light receiving element 13 such as a semiconductor position sensor as a light receiving portion. The other end surface 11b of the optical fiber bundle 11 is
The optical system is guided to a distant position through the frame 2.
An image pickup surface 15a of a CCD camera 15 as an image pickup means through
Facing. The output code 15b of the CCD camera 15 is connected to the calculator 9 described above. The image receiving surface 11a of the optical fiber bundle 11 is arranged at the image forming position of the convex surface 4a of the surface S to be measured, and the measuring light beam L ₁ emitted from the light emitting element 12 through the light projecting lens 12a is measured. Center line A of surface S
Although it proceeds toward the upper point O, it is refracted by passing through the wedge-shaped cylindrical lens 4b and is incident on the measurement point P ₁ at a position eccentric from the center line A of the surface S to be measured by a predetermined deviation amount R. .
The light beam L ₂ reflected at the measurement point P ₁ passes through the cylindrical lens 4b again and enters the light receiving element 13 via the light receiving lens 13a, and the light receiving signal of the light receiving element 13 is the code 13b.
Is input to the calculator 9 via. With such an optical arrangement, when the compound lens frame 4 is rotationally driven by the motor 6, the cylindrical lens 4b rotates and the light rays L ₁ and L ₂
The eccentric direction with respect to is changed, whereby the measurement point P ₁ is turned around the center line A with a radius (eccentricity amount) R.

In addition, the lower end of the main body 3 is provided with a substantially cylindrical transparent cover 3c extending downward, and the drive shaft of the motor 6
6a is covered with a cover 3d.

Operation of Embodiment Next, the operation of the embodiment of the present invention configured as described above will be described.

First, as shown in FIG. 1, the optical normal scribing detection apparatus 1 is brought close to the surface S to be measured, and the center line A is applied to the surface S to be measured in a posture substantially perpendicular to the surface S to be measured. The frame 2 is set to a position facing the marked marking line M, and the frame 2 is temporarily fixed to the surface S to be measured in this state. The center line A of the detection device 1 coincides with the head axis of the processing machine, for example.

At this time, the field of view (imaging screen) of the CCD camera 15 is, for example, as shown in FIG. 2, and the position of the scribing line M with respect to the center line A is processed by processing this image signal by the calculator 9. , That is, center line A (field of view O)
And the angle of rotation ω between the vertical line and the tangent of the foot are calculated. Then, the calculated shift amount δ and rotation angle ω intersect the current detection point of the optical normal scribing detection device 1, that is, the center line A of the optical normal scribing detection device 1 and the surface S to be measured. From the coordinates (X, Y, Z) of the point and the attitude of the optical normal scribing detection apparatus 1, that is, data indicating the measurement direction, the shift amount δ is decomposed into components in the x, y, and z directions, and is appropriately adjusted. Scribing line M by moving the frame 2 by a simple drive mechanism
Correct the position with respect to.

After that, by rotating the motor 6, the compound lens frame 4 is driven to rotate via the timing belt 7. By rotating the compound lens frame 4, the compound lens
Of the 4c, the central convex lens 4a does not affect the image formation on the image receiving surface 11a of the optical fiber bundle 11 because it only rotates about its optical axis, that is, the center line A coinciding therewith, but the cylindrical lens 4b. Means that the measuring point P ₁ of the light beam L ₁ from the light emitting element 12 to the surface S to be measured is turned while maintaining a constant eccentricity R with respect to the center line A. This measurement point P ₁
Is a circular orbit with a radius R centered on the center line A in the plane of the surface S to be measured.

At this time, if the measured surface S is three-dimensionally parallel to the plane perpendicular to the center line A, from the reference surface at the lower end of the compound lens frame 4 to the measured surface S along the center line A. The distance D is always constant during the rotation of the compound lens frame 4.
However, if the surface S to be measured is not perpendicular to the center line A, the distance D changes periodically during one rotation. The distance detector 10 converts the change in the distance D into an electric analog amount as a change in the amount of received light due to the movement of the image of the light receiving element 13, and sends it to the calculator 9.

Therefore, the calculator 9 sequentially calculates the phase angle θ of the compound lens frame 4 during rotation based on the signal from the rotary encoder 8, and the compound lens frame 4 based on the magnitude of the signal from the light receiving element 13 at that time. The distance D from the reference surface to the measured surface S to be measured is calculated, the phase angle θ and the distance D at that time are sequentially read, and a sine curve having a relationship as shown in FIG. Based on the relationship, the phase angle θ _max and the phase angle θ _min that give the maximum value D _max and the minimum value D _min of the sinusoidal curve are obtained, and the distance D ₀ at the phase angle θ _{0 that} is deviated from this phase angle value by 90 degrees is obtained. Note that the distance D ₀
Represents the average distance from the compound lens frame 4 to the surface S to be measured. Here, the phase angles θ _max and θ _min represent the tilt direction of the surface S to be measured, and the difference (D _max −D _min ) between them represents the tilt amount.

 In addition, theoretically, the inclination angle α is obtained by the following formula.

α = arctan [(D _max −D _min ) / 2R] Thus, the calculator 9 causes the error between the center line A of the compound lens frame 4 and the normal line of the surface S to be measured, that is, the tilt direction and An optical normal scribing detection device is provided with information in a direction in which the amount of tilt is calculated to correct this error, that is, in a direction in which the center line A of the compound lens frame 4 is made to coincide with the normal line of the surface S to be measured. The output of 1 is output to a posture control device of a processing machine (not shown).

Now, FIG. 3 (B) is a graph showing the relationship between the convex corner and the surface S to be measured. The maximum value D _max1 corresponds to the flat surface portion, and the maximum value D _max2 corresponds to the bent corner portion.
The minimum value D _min does not appear. Therefore, in this case, the tilt amount is obtained by 2 × (D _max1 −D ₀ ).

Further, FIG. 3C is a graph of the surface S to be measured of the concave corner, in which the minimum value D _min1 is in the plane portion and the minimum value D is
_min2 corresponds to the bent portion, but in this case, the maximum value D _max does not appear. In this case, the amount of tilt is _calculated from 2 × (D ₀ −D _min1 ).

EFFECTS OF THE INVENTION As described above, according to the present invention, means for rotating the compound lens system and outputting a signal corresponding to the rotation phase thereof is provided, and the marking line of the measured surface imaged by the compound lens system is provided. An optical system that detects the position error between the centerline and the scribing line by imaging, and measures the distance to the surface to be measured from the center of rotation on the surface to be measured through the compound lens system at a position with a predetermined eccentric amount. A distance measuring means is provided, the measurement axis is brought close to the surface to be measured at the time of measurement, and then the measuring point of the optical distance measurement is turned by the rotation of the complex lens system, thereby making the reference surface and the surface to be measured. Since the direction of the normal error and the magnitude thereof are calculated by calculation from the distance measurement signal generated according to the distance and the signal corresponding to the rotation phase, the tip of the detection device is formed small. Bonito Since the structure is simple, the normal line of the capacitance type or the magnetic type that has been used in the past even when the vicinity of the surface to be measured is sharply bent or has a cutting groove, or is the end of the material Compared with the detection device, it is possible to measure the inclination of the surface to be measured in a measurement range having a very small radius, that is, substantially at the position of the measurement point, and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an essential part of an embodiment of an optical normal scribing detection apparatus according to the present invention, and FIG. 2 is a schematic view showing an example of an image pickup screen by a CCD camera in the apparatus of FIG. 3 (a), (b), and (c) are graphs showing the relationship between the rotational phase angle of the measuring axis and the distance obtained by the apparatus of FIG. 1 in the case of measuring surfaces of various shapes. 1 ... Optical normal scribing detection device, 2 ... Frame, 3
...... Main body, 3a Bearing, 4 Complex lens frame, 6 Motor, 7 Timing belt, 8 Rotary encoder, 9 Calculator, 10 Distance detector, 11 Optical fiber Bundle, 12 …… Light emitting element, 13 …… Light receiving element, 15 …… CC
D camera.

Claims (4)

[Claims] 1. A compound lens system rotatably supported about a center line, which is substantially perpendicular to a surface to be measured and having a marking line, and a rotational phase of the compound lens system. Drive detecting means for detecting the distance, imaging means for observing the image of the marking line formed by the compound lens system at an appropriate position, and optical distance measurement for measuring the distance to the surface to be measured through the compound lens system. Means for detecting the position error between the center line and the scribe line by image-processing the signal from the image pickup means, and a distance measurement signal and a rotation phase which change with the rotation of the compound lens system. By calculating the relationship pattern of, the inclination direction and the amount of inclination with respect to the normal to the scribe line applied to the measured surface of the center line and the distance from the reference surface to the measured surface Optical normal marking detection device according to claim. 2. A complex lens system, a convex lens at the center of rotation, and a wedge-shaped cylindrical lens around the convex lens. The convex lens allows a marking line on the surface to be measured to be located behind the complex lens system. The optical normal scribing detection device according to claim 1, wherein an image is formed, and a measurement point of the optical distance measurement is swiveled around a center line by rotation of a compound lens system. 3. An illumination unit for irradiating the optical distance measuring means from a direction inclined by a predetermined angle with respect to a center line,
The optical normal scribing detection device according to claim 1, characterized in that the optical normal scribing detection device is configured by a light receiving portion that captures a light ray reflected from one point at a predetermined angle on the opposite side of the center line. 4. An optical normal scribing detection apparatus according to claim 1, wherein said image pickup means comprises an optical fiber bundle, an electronic camera and a necessary lens system.