JPH10103937A - Optical axis inclination measuring method for laser light and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical axis inclination measuring method of laser light which can conduct accurate calculation of an irradiated position on an object which is irradiated with the laser light and an optical axis inclination measuring device to which this method is applicable. SOLUTION: A laser sensor is set at an initial position to measure a first measuring distance L1 between the laser sensor and a jig when an angle of rotation of the jet is set at 0 deg. and then, a second measuring distance L2 is measured between the laser sensor and the jig when the angle of rotation of the jig is set at 180 deg.. When a difference (|IL1-L2|) between the measured distances is larger than a preset criterion value ε, the laser sensor is moved by a preset moving pitch on a linear axis to perform the processing again following the step 2. On the other hand, when the difference (|L1-L2|) is smaller than the preset criterion value ε, the inclination θ of the optical axis of a laser light is calculated based on the current position (d) of the laser sensor when the initial position at this moment is used as reference, the first measuring distance L1 or the second measuring distance L2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the shape of an object to be measured by irradiating the surface of the object with laser light, and more particularly, to accurately irradiating a position of an object on the object irradiated with the laser light. The present invention relates to a method for calculating an irradiation position of a laser beam, which can be calculated.

[0002]

2. Description of the Related Art In a method of measuring the shape of an object to be measured, a method using a laser beam having a high directivity can ensure a high measurement accuracy, and therefore requires a high accuracy such as a roundness measurement of a sphere or a cylindrical structure. It has been widely used for measurements to be made. When measuring the surface shape of an object to be measured by laser light emitted from an integrated light-emitting / light-receiving laser sensor that integrates a light emitter and a light receiver, either or both of the laser sensor and the object to be measured By moving the laser sensor and the object to be measured relatively,
In this way, scanning is performed on the measurement site of the measurement object, for example, the contour of an arbitrary cross section or the entire surface. Generally, in such a light emitting / receiving laser type integrated laser sensor, the object to be measured is irradiated with laser light, the reflected light is received, and the laser light on the object to be measured is applied using a principle such as trigonometry. The irradiation position is measured. Specifically, an irradiation position on the measurement object irradiated with the laser light is calculated from the position of the laser sensor and the light receiving position of the reflected light at the light receiving section of the laser sensor.

[0003]

However, in the integrated light emitting / receiving laser sensor, the laser light radiated to the outside through the condensing lens is covered by an error in mounting the converging lens built in the sensor. There is a case where the irradiation position on the measurement object is not accurately irradiated. Specifically, the laser light is irradiated at an angle of about 0.1 ° with respect to the designed optical axis for projecting light to the irradiation position due to the mounting error of the condenser lens of about several μm. There is. And
By irradiating the laser beam at an angle of 0.1 ° with respect to the designed optical axis, the coordinates of the irradiation position calculated from the measurement data are shifted from the actual coordinates by several tens μm in the vertical direction. . For example, in a laser sensor having a focal length of 50 mm, when the laser beam is irradiated at an angle of 0.1 ° with respect to the designed optical axis, the irradiation position calculated from the measurement data is the position actually irradiated. 87 μm vertically
Measurement error occurs. This degree of measurement error is not so problematic when the object to be measured is sufficiently large compared to the focal length of the laser sensor.However, when the object to be measured is small compared to the focal length of the laser sensor, When the contour shape of an object is complicated, the measurement error cannot be ignored. Therefore, depending on an object to be measured, it is necessary to correct a measurement error caused by the inclination of the optical axis of the laser light.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an optical axis of a laser beam, which makes it possible to accurately calculate an irradiation position on an object to be measured irradiated with the laser light. An object of the present invention is to provide a tilt measuring method and an optical axis tilt measuring device to which the measuring method is applied.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a measuring surface having a rotation axis and being inclined by a predetermined inclination angle α with respect to a plane perpendicular to the rotation axis. A jig having a rotation axis, a rotation axis driving mechanism for rotating the rotation axis, and a linear axis orthogonal to the rotation axis, and mounted on the linear axis such that the optical axis in design of the laser light is in a parallel relationship with the rotation axis. In the laser beam optical axis inclination measuring device having the integrated light emitting and receiving laser sensor and a linear axis driving mechanism for moving the laser sensor in the axial direction of the linear axis, the rotation angle of the jig is set to 0 °. The first measurement distance L1 between the laser sensor and the jig at this time is measured, and then the rotation angle of the jig is set to 180 °, and the second measurement between the laser sensor and the jig at this time is performed. Measure the distance L2, and finally, First distance L1, a second distance L2,
And a method for measuring the inclination of the optical axis of the laser light, wherein the inclination θ of the optical axis of the laser light is calculated from the inclination angle α of the jig.

[0006] With the configuration according to the first aspect,
The inclination θ of the optical axis of the laser beam can be easily calculated from the measured distances when the rotation angle of the jig is 0 ° and 180 ° and the inclination angle α set at the time of designing the jig.
Note that the measurement distance between the laser sensor and the jig refers to the distance between the laser sensor and a laser beam emitted from the laser sensor when the laser beam irradiates an arbitrary point on the measurement surface of the jig.

By the way, the jig inclination angle α when the jig 21 is mounted on the measuring device includes an error in the manufacture of the jig and an error in the mounting of the jig when compared with a design value. The inclination θ of the optical axis of the laser light calculated by the above is affected by the error of the jig inclination angle α. If the object to be measured is sufficiently large compared to the focal length of the laser sensor, the accuracy of the inclination θ of the optical axis of the laser light calculated by the influence of the error of the jig inclination angle α does not matter so much, When the size of the measured object is smaller than the focal length of the laser sensor and the contour shape of the measured object is complicated, the inclination θ of the optical axis of the laser light calculated by the measuring method according to claim 1 is calculated. The accuracy is not negligible.

Therefore, in the invention according to claim 2, a jig having a rotation axis and having a measurement surface inclined by a predetermined inclination angle with respect to a plane orthogonal to the rotation axis, a rotation axis driving mechanism for rotating the rotation axis, , A linear axis orthogonal to the rotation axis,
An integrated laser sensor that emits and receives light on a linear axis so that the designed optical axis of the laser beam is parallel to the rotation axis, and a straight line that moves this laser sensor in the axial direction of the linear axis The laser sensor is set to an initial position (step 1), the jig rotation angle is set to 0 ° (step 2), and the laser sensor at this time is set. And jig first
Is measured (step 3), the rotation angle of the jig is set to 180 ° (step 4), and the second measurement distance L2 between the laser sensor and the jig at this time is measured (step 3). 5) If the difference (| L1−L2 |) between the first measurement distance L1 and the second measurement distance L2 is larger than a predetermined judgment value ε (step 6N), the laser sensor is moved on the linear axis. It is moved by a predetermined moving pitch (step 7), and the processing after step 2 is performed again. On the other hand, when the difference (| L1−L2 |) is smaller than the predetermined judgment value ε (step 6Y) ), The inclination θ of the optical axis of the laser beam is calculated from the current position d of the laser sensor based on the initial position at this time and the first measurement distance L1 or the second measurement distance L2. The feature of It provided the optical axis inclination measuring method Heather light.

According to the configuration of the second aspect,
The inclination θ of the optical axis of the laser light is determined by comparing the current position d of the laser sensor with respect to the initial position and the first measurement distance L
This is calculated based on the first or second measurement distance L2, and the jig inclination angle α is not considered.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, the initial position of the laser sensor is set on the rotation axis. As a result, the initial position is set at a position where the designed optical axis of the laser beam irradiates the intersection P between the rotation axis and the measurement surface 21a of the jig.
Difference between the measured distance L1 and the second measured distance L2 (| L1-
L2 |) quickly becomes smaller than the determination value ε (by a small number of loops).

According to a fourth aspect of the present invention, in addition to the configuration of the second or third aspect, the movement pitch of the laser sensor is equal to the difference (| L1-L1) between the first measurement distance L1 and the second measurement distance L2. L2 |) multiplied by a constant k. If the movement pitch of the laser sensor is too large, an oscillation phenomenon occurs, and the difference (| L1−L2 |) does not converge. Conversely, if the movement pitch is too small, the number of loops from step 2 to step 7 increases. Difference (| L1-L2
The processing time until |) converges becomes longer.
With the configuration described in claim 4, if the value of the constant k is properly selected, no oscillation phenomenon occurs, and the processing time does not become long.

According to a fifth aspect of the present invention, there is provided an apparatus to which the method for measuring the optical axis inclination of a laser beam according to any one of the first to fourth aspects is applied. A jig with an inclined measurement surface, a rotation axis drive mechanism that rotates the rotation axis, a linear axis perpendicular to the rotation axis, and a linear axis so that the optical axis in the design of the laser beam is parallel to the rotation axis. And a linear axis drive mechanism for moving the laser sensor in the axial direction of the linear axis, wherein the jig rotation angles are 0 ° and 180 °, respectively. The inclination of the optical axis of the laser light is calculated based on two measurement values measured by the laser light irradiated on the measurement surface in the state of (1).

According to a sixth aspect of the present invention, in addition to the configuration of the fifth aspect, the rotary shaft driving mechanism is a servomotor with an encoder. This makes it possible to position the jig rotational position with high accuracy.

According to a seventh aspect of the present invention, in addition to the configuration of the fifth or sixth aspect, the linear axis drive mechanism is a combination of a servo motor with an encoder and a ball screw. Thus, the position on the linear axis of the laser sensor can be positioned with high accuracy.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 4, a jig 21 having a rotation axis in the horizontal direction and a measurement surface 21a inclined at a certain angle with respect to a plane orthogonal to the rotation axis is set. Furthermore, the optical axis in the design of the laser beam is
The laser sensor 23 is installed so as to be coaxial with the rotation axis of. At this time, if the laser beam emitted from the laser sensor 23 is irradiated in the true horizontal direction as designed, the actual optical axis of the laser beam will be coaxial with the rotation axis of the jig 21. Jig 2 shown in FIG.
1 and the posture when the posture of the jig 21 is rotated by 180 ° with respect to FIG. 4A, that is, the laser sensor 23 in the posture shown in FIG. 4B. Is equal to the distance measured because the point on the measurement surface 21a of the jig irradiated with the laser beam is the same.

However, assuming that the laser light emitted from the laser sensor 23 is not irradiated in the horizontal direction as designed as shown in FIG. 5, the laser in the posture of the jig 21 shown in FIG. The distance measured by the sensor 23;
The attitude when the attitude of the jig 21 is rotated by 180 ° with respect to FIG. 5A, that is, the distance measured by the laser sensor 23 in the attitude shown in FIG. Are not equal because the points on the measurement surface 21a are not the same. In the present embodiment, the inclination of the optical axis of the laser beam is obtained by utilizing this phenomenon.

FIG. 3 shows an example of a laser light optical axis inclination measuring apparatus to which the method for calculating a position to be irradiated with laser light in the present embodiment is applied. Rotary shaft drive mechanism 22
The jig 21 attached to the rotating shaft has a measuring surface 21a inclined at a fixed angle with respect to a surface orthogonal to the rotating shaft. The entire shape of the jig 21 may be a substantially cylindrical shape having a rotation axis as a central axis, but is not limited to this, and may be a substantially rectangular parallelepiped as long as it has an inclined cutout (cross section). On the other hand, the linear axis of the linear axis drive mechanism 24 is orthogonal to the rotation axis of the rotary axis drive mechanism 22, and the laser sensor 23 attached to the linear axis is movable along the linear axis. Fine adjustment is possible so that the optical axis in design is perpendicular to the linear axis.

The controller 26 inputs measurement data obtained by the laser sensor 23, performs predetermined processing, and outputs a movement command for operating the rotary shaft driving mechanism 22 and the linear shaft driving mechanism 24. Driver 25
Operates the rotation axis drive mechanism 22 and the linear axis drive mechanism 24 in accordance with the movement command from the controller 26. here,
Describing the configurations of the rotary axis drive mechanism 22 and the linear axis drive mechanism 24, both encoders (position detectors) and hydraulic or pneumatic actuators may be servo-controlled. In the present embodiment, the rotational position of the jig 21 is determined. In order to perform high-precision positioning, a servomotor with an encoder is used as the rotation axis drive mechanism 22, and the optical axis in design of the laser sensor 23 is made to exactly match the rotation axis of the rotation axis drive mechanism 22. It is necessary to use the linear axis drive mechanism 2
A servo motor provided with an encoder and a ball screw for accurately converting the rotary motion of the servo motor into a linear motion are used as 4.

The laser beam tilt measuring device shown in FIG. 3 can be used as a single measuring unit, but is generally used in combination as a part of a measuring device (not shown) for measuring an object to be measured. It is. in this case,
The linear axis drive mechanism 24 is used when the laser sensor 23 is moved to the measurement position of the optical axis shown in FIG.
It will also be used when measuring the shape of the object to be measured.

Next, a first measuring method for measuring the inclination of the optical axis of the laser light in this embodiment will be described. As shown in FIG. 6, the angle formed between the measurement surface 21a of the jig and the plane orthogonal to the rotation axis, that is, the inclination angle is α (hereinafter, referred to as “jig inclination angle α”). The jig inclination angle α is a value selected when designing the jig 21. As shown in FIG. 6A, the measured value of the laser sensor 23 when the rotation angle of the rotating shaft drive mechanism 22 is 0 ° is L1 (hereinafter referred to as “measured value L1 when the jig rotation angle is 0 °”). As shown in FIG. 6B, the measured value of the laser sensor 23 when the rotation angle of the rotation shaft drive mechanism 22 is set to 180 ° is L2 (hereinafter referred to as “jig rotation angle 180 °”).
In this case, the actual distance L (hereinafter, referred to as “actual distance L”) from the point of emission of the laser beam to the intersection P between the rotation axis and the measurement surface 21a of the jig is expressed as , (1) and (2). Here, θ is the angle between the designed optical axis of the laser light and the actual optical axis of the laser light, that is, the inclination of the optical axis of the laser light.

[0021]

(Equation 1)

In Equations (1) and (2), the unknowns are the actual distance L and the inclination θ of the optical axis of the laser beam. Therefore, the actual distance L is calculated from Equations (1) and (2). Equation (3) for erasing and calculating the inclination θ of the optical axis of the laser beam is derived.

[0023]

(Equation 2)

As shown in equation (3), the inclination θ of the optical axis of the laser beam is determined by the measured value L1 when the jig rotation angle is 0 °, the measured value L2 when the jig rotation angle is 180 °, and the jig inclination angle. α
It will be calculated from:

FIG. 2 is a flowchart showing the first measuring method. That is, the rotation angle of the jig 21 is set to 0 ° (step 11), and the distance L1 between the laser sensor 23 and the jig 21 at this time is measured (step 12). Next, the rotation angle of the jig 21 is set to 180 ° (step 13), and the laser sensor 23 at this time is set.
The distance L2 between the tool and the jig 21 is measured (step 14).
Finally, the inclination θ of the optical axis of the laser beam is calculated by the equation (3) (step 15).

In equation (3), the jig inclination angle α affects the calculated inclination θ of the optical axis of the laser beam. The jig inclination angle α is an angle defined by design. The actual jig inclination angle α includes a slight error due to a jig manufacturing error as compared with a design value. To cope with this, even if the actual jig inclination angle α is measured for the manufactured jig 21, the measurement error at this time cannot be completely eliminated. Also, the mounting error when mounting the jig 21 to the measuring device shown in FIG. 3 cannot be completely excluded. Therefore, the jig inclination angle α when the jig 21 is attached to the measuring device includes the above error when compared with the design value, and the inclination θ of the optical axis of the laser light calculated by the equation (3) is And the error of the jig inclination angle α.

When the object to be measured is sufficiently large compared to the focal length of the laser sensor 23, the accuracy of the inclination θ of the optical axis of the laser light calculated due to the influence of the error of the jig inclination angle α is not so problematic. Therefore, there is no problem even in the first measuring method. However, when the size of the object to be measured is smaller than the focal length of the laser sensor 23 and the contour shape of the object to be measured is complicated, the optical axis of the laser light calculated by the first measuring method is used. The accuracy of the inclination θ cannot be ignored.

Therefore, even when the size of the object to be measured is smaller than the focal length of the laser sensor 23 and the contour of the object to be measured is complicated, the inclination θ of the optical axis of the laser beam is calculated with high accuracy. A second possible measurement method is proposed. In the first measurement method, the influence of the error of the jig inclination angle α has become a problem, and therefore, in the second measurement method, the jig inclination angle α
The inclination θ of the optical axis of the laser light is determined without using the equation.

If the point on the measuring surface 21a of the jig irradiated with the laser beam is a point P on the rotation axis of the jig 21,
Regardless of the rotation angle of the jig 21, the laser beam
So that the measured value of the laser sensor 23 is jig 2
It should always be the same regardless of the rotation angle of one. This is used in the second measurement method.

In other words, if the laser sensor 23 can be positioned on a linear axis so that the measured value of the laser sensor 23 does not change even if the jig 21 is rotated,
At this time, the inclination θ of the optical axis of the laser light is obtained by Expression (4) as shown in FIG. In the equation (4), d is the distance between the emission position of the laser beam and the rotation axis. Further, in the equation (4), instead of the measurement distance L1 when the rotation angle of the jig 21 is 0 °, a measurement distance L2 when the rotation angle is 180 ° may be used.

[0031]

(Equation 3)

FIG. 1 shows a flowchart of the second measuring method. First, the linear axis drive mechanism 24
Is operated to set the laser sensor 23 to the initial position (step 1). The initial position of the laser sensor 23 may be any position as long as the laser light irradiates the measurement surface 21a of the jig, but in the present embodiment, the designed optical axis of the laser light is parallel to the rotation axis. In consideration of this, the initial position may be set at a position where the designed optical axis of the laser beam irradiates the intersection P between the rotation axis and the measurement surface 21a of the jig. Thereby, the emission position of the laser beam at the initial position of the laser sensor 23 is present on the rotation axis. The following steps 2 to 5 are the same as steps 11 to 14 in the first measurement method described above. That is, the rotation angle of the jig 21 is set to 0 ° (Step 2), the distance L1 between the laser sensor 23 and the jig 21 at this time is measured (Step 3), and then the rotation angle of the jig 21 is set to 180 °. Then, the distance L2 between the laser sensor 23 and the jig 21 at this time is measured (Step 5).

As described above, the point on the measurement surface 21a of the jig irradiated with the laser beam is the point P on the rotation axis of the jig 21.
Then, the laser beam irradiates the point P irrespective of the rotation angle of the jig 21, so that the measured value of the laser sensor 23 is always the same regardless of the rotation angle of the jig 21. The difference between the measured value L1 when the jig rotation angle calculated at Step 3 is 0 ° and the measured value L2 when the jig rotation angle calculated at Step 5 is 180 ° (|
If L1−L2 |) becomes 0, the irradiation position of the laser light on the measurement surface 21a at this time becomes the point P on the rotation axis, and therefore, the inclination θ of the optical axis of the laser light is calculated by Expression (4). That's all I need to do. On the other hand, the difference (| L1-L2 |) is 0
If not, the laser light measurement surface 21 at this time
It is determined that the irradiation position on a is not the point P on the rotation axis, the laser sensor 23 is moved on the linear axis by a predetermined amount, and then the processing after step 2 is repeated again.

More specifically, the measured value L1 when the jig rotation angle is 0 ° and the measured value L1 when the jig rotation angle is 180 °
It is rare that the difference (| L1-L2 |) with respect to 2 completely becomes 0, so the determination value ε is set in advance, and the difference (| L1-L2 |
|) Is equal to or smaller than the determination value ε (step 6).
Y), the difference (| L1-L2 |) is determined to be almost 0,
The inclination θ of the optical axis of the laser light is calculated by the equation (4) (step 8). On the other hand, if the difference (| L1-L2 |) is larger than the judgment value ε (step 6N), the difference (| L1-L2 | )
Is determined not to be 0, the laser sensor 23 is moved by a predetermined pitch on the linear axis (Step 7), and Step 2 is performed again.
The following processing is performed. The magnitude of the determination value ε depends on the precision with which the inclination θ of the optical axis of the laser light is to be obtained, but generally a value of about several microns is sufficient.
When the determination value ε is set to be large, Steps 2 to 7
Since the number of times of the loop is reduced, the calculation time is reduced, but the accuracy of the inclination θ of the optical axis of the obtained laser light is reduced. Conversely, if the determination value ε is set to be small, the number of loops increases and the calculation time increases, but the accuracy of the inclination θ of the optical axis of the obtained laser light increases.

Here, the moving pitch and the moving direction of the laser sensor 23 in step 7 will be described in detail. The moving pitch of the laser sensor 23 is a value obtained by multiplying the difference (| L1-L2 |) by a constant k. If the constant k is too large, an oscillation phenomenon occurs, and the difference (| L1−L2 |) does not converge. Conversely, if the constant k is too small, the number of loops from step 2 to step 7 increases, and the difference (| | L1-L2
Since the processing time until |) converges becomes longer, it is necessary to set an appropriate value. As a result of several experiments, it has been found that if the constant k is selected in the range of 0.3 to 0.5, no oscillation phenomenon occurs and the processing time does not become long. The moving direction of the laser sensor 23 is a direction in which the difference (| L1-L2 |) converges, and (L1-L2)
It is determined by the sign of 2).

As described above, the laser sensor 2
Since the emission position of the laser light at the initial position of 3 exists on the rotation axis, the distance d between the emission position of the laser light and the rotation axis in Expression (4) is based on the initial position of the laser sensor 23. This is calculated as the cumulative value of the movement amount of the laser sensor 23 in Step 7 at that time.

Finally, based on the inclination θ of the optical axis of the laser light calculated in the first or second measuring method described above,
The true coordinates of a point on the measurement surface 21a of the jig irradiated with the laser light are obtained. As shown in FIG. 8, the measurement surface 21 of the jig illuminated by the coordinates calculated from the measurement values of the laser sensor 23, that is, the optical axis in the design of the laser light.
Assuming that the coordinates of a point on a are (x ₀ , y ₀ ) and the distance measured by the laser sensor 23 at this time is L ₀ , the true value of the point on the measurement surface 21 a of the jig irradiated with the laser light is obtained. The coordinates (x ₁ , y ₁ ) are obtained by the equation (5) from the inclination θ of the optical axis of the laser light calculated in the first or second measurement method.

[0038]

(Equation 4)

When the optical axis tilt measuring device of the laser beam is used as an independent measuring unit and only the first measuring method is used, the optical axis in the design of the laser sensor 23 is changed to the rotational axis driving mechanism 22. If the laser sensor 23 can be fixed so as to be exactly coincident with the rotation axis, there is no need to move the laser sensor 23, so that the linear axis drive mechanism 24 becomes unnecessary.

[0040]

According to the first or fifth aspect of the present invention, a jig having a rotation axis and having a measurement surface inclined at a predetermined inclination angle α with respect to a plane perpendicular to the rotation axis; A rotation axis driving mechanism for rotating the rotation axis, a linear axis orthogonal to the rotation axis, and a light projection / light source mounted on the linear axis so that the designed optical axis of the laser light is in a parallel relationship with the rotation axis.
In a laser beam optical axis tilt measuring device having a light receiving integrated laser sensor and a linear axis drive mechanism for moving the laser sensor in the axial direction of the linear axis, the jig rotation angles are 0 ° and 180 °, respectively. In this case, the inclination θ of the optical axis of the laser beam can be easily calculated based on the measurement distance and the inclination angle α set at the time of designing the jig.

According to the second or fifth aspect of the present invention, the laser sensor is set at the initial position, the rotation angle of the jig is set to 0 °, and the first measurement between the laser sensor and the jig at this time is performed. The distance L1 is measured, then the rotation angle of the jig is set to 180 °, the second measurement distance L2 between the laser sensor and the jig at this time is measured, and the first measurement distance L1 is measured.
When the difference (| L1−L2 |) between the second measurement distance L2 and the second measurement distance L2 is larger than a predetermined determination value ε, the laser sensor is moved on a linear axis by a predetermined movement pitch,
The processing after step 2 is performed again. On the other hand, if the difference (| L1−L2 |) is smaller than the preset determination value ε, the current position of the laser sensor based on the initial position at this time is used. The inclination θ of the optical axis of the laser light is calculated based on d and the first measurement distance L1 or the second measurement distance L2. Therefore, the inclination θ of the optical axis of the laser light is calculated based on the initial position. Current position of the laser sensor at the time of the first measurement distance L1 or the second measurement distance L
Therefore, the jig inclination angle including a manufacturing error and a mounting error is not taken into consideration. This makes it possible to accurately calculate the inclination θ of the optical axis of the laser beam even when the size of the object is smaller than the focal length of the laser sensor and the contour of the object is complicated. It became.

According to the invention of claim 3, according to claim 2,
According to the invention, the initial position of the laser sensor is set on the rotation axis. Therefore, the initial position is set at a position where the designed optical axis of the laser beam irradiates the intersection of the rotation axis and the measurement surface of the jig, and the first measurement distance L1 and the second measurement distance L2 are set. Difference (| L1-L2
|) Quickly becomes smaller than the judgment value ε (by a small number of loops), thereby shortening the processing time.

According to the invention according to claim 4, claim 2 is provided.
In the invention according to the third aspect, the moving pitch of the laser sensor is a value obtained by multiplying a difference (| L1−L2 |) between the first measurement distance L1 and the second measurement distance L2 by a constant k. Therefore, by appropriately selecting the value of the constant k, it is possible to suppress the occurrence of an oscillation phenomenon due to the movement pitch being too large, and the increase in processing time due to the movement pitch being too small.

According to the invention of claim 6, according to claim 5,
In the present invention, the rotary shaft driving mechanism is a servomotor with an encoder. Therefore, it has become possible to position the jig rotational position with high accuracy.

According to the invention of claim 7, claim 5
In the invention according to the sixth aspect, the linear axis driving mechanism is a combination of a servomotor with an encoder and a ball screw. Therefore, the position on the linear axis of the laser sensor can be positioned with high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a flowchart of a first measurement method according to an embodiment of the present invention.

FIG. 2 is a view showing a flowchart of a second measurement method in the embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a laser light optical axis inclination measuring apparatus to which a method for calculating a position to be irradiated with laser light according to an embodiment of the present invention is applied.

FIG. 4 shows the laser sensor 23 and the jig 21 when the optical axis of the laser beam is emitted coaxially with the rotation axis of the jig 21.
FIGS. 6A and 6B are diagrams showing a positional relationship between the jig 21 and the jig 21 when the rotation angle of the jig 21 is 0 °.
Respectively.

5A and 5B are diagrams illustrating a positional relationship between the laser sensor and the jig when the actual optical axis of the laser light is emitted obliquely with respect to the designed optical axis. FIG.
When the rotation angle of the jig 21 is 0 °, FIG.
80 ° is shown.

FIG. 6 is a diagram showing the relationship between the inclination θ of the optical axis of the laser beam, the jig inclination angle α, and the measurement value of the laser sensor 23;
(A) shows the case where the rotation angle of the jig 21 is 0 °, and (b) shows the case where the rotation angle of the jig 21 is 180 °.

7A and 7B are diagrams showing the relationship between the inclination θ of the optical axis of the laser light, the distance d between the emission position of the laser light and the rotation axis, and the measurement value of the laser sensor 23. FIG. 7A shows the rotation angle of the jig 21. Is 0 °, and (b) shows the case where the rotation angle of the jig 21 is 180 °.

FIG. 8 shows the coordinates (x ₀ , y ₀ ) calculated from the measured value L ₀ of the laser sensor 23 and the true coordinates (x ₁ , y _{1) of} a point on the measurement surface 21a of the jig irradiated with the laser beam. FIG. 3) is a diagram showing the relationship between the optical axis of the laser beam and the inclination θ of the laser beam.

[Explanation of symbols]

 Reference Signs List 21 Jig 21a Measurement surface of jig 22 Rotary axis drive mechanism 23 Laser sensor 24 Linear axis drive mechanism

Claims (7)

[Claims] 1. A jig having a rotation axis and having a measurement surface inclined by a predetermined inclination angle α with respect to a plane orthogonal to the rotation axis, a rotation axis driving mechanism for rotating the rotation axis,
A linear axis orthogonal to the rotation axis, a light emitting / receiving integrated laser sensor mounted on the linear axis such that a designed optical axis of the laser light is in a parallel relationship with the rotation axis; A linear axis driving mechanism for moving a laser sensor in the axial direction of the linear axis; an optical axis tilt measuring device for laser light, wherein the rotation angle of the jig is set to 0 °, and the laser sensor and the jig at this time are set. Then, the rotation angle of the jig is set to 180 °, the second measurement distance L2 between the laser sensor and the jig at this time is measured, and finally, A method for measuring an inclination of an optical axis of a laser beam, wherein the inclination θ of the optical axis of the laser beam is calculated from the first distance L1, the second distance L2, and the inclination angle α of the jig. 2. A jig having a rotation axis and having a measurement surface inclined by a predetermined inclination angle with respect to a plane perpendicular to the rotation axis, a rotation axis drive mechanism for rotating the rotation axis, and a rotation axis driving mechanism. An orthogonal linear axis, a light emitting / receiving integrated laser sensor mounted on the linear axis such that the designed optical axis of the laser light is in parallel with the rotation axis, and the laser sensor In a laser beam optical axis tilt measuring device having a linear axis driving mechanism for moving in the axial direction of a linear axis, the laser sensor is set to an initial position (step 1), and the rotation angle of the jig is set to 0 ° (Step 2), a first measurement distance L between the laser sensor and the jig at this time.
1 is measured (Step 3). Next, the rotation angle of the jig is set to 180 ° (Step 4), and a second measurement distance L2 between the laser sensor and the jig at this time is measured (Step 5). If the difference (| L1−L2 |) between the first measurement distance L1 and the second measurement distance L2 is larger than a predetermined judgment value ε (step 6N), the laser sensor is moved to the linear axis. It is moved by the previously set moving pitch (step 7), and the processing after step 2 is performed again. On the other hand, if the difference (| L1-L2 |) is smaller than the predetermined judgment value ε, (Step 6Y), the current position d of the laser sensor based on the initial position at this time
And the first measurement distance L1 or the second measurement distance L2
Wherein the inclination θ of the optical axis of the laser light is calculated. 3. The method according to claim 2, wherein an initial position of the laser sensor is set on the rotation axis. 4. A movement pitch of the laser sensor is a difference (| L1) between the first measurement distance L1 and the second measurement distance L2.
The method for measuring the optical axis inclination of a laser beam according to claim 2 or 3, wherein a value obtained by multiplying -L2 |) by a constant k is used. 5. A jig having a rotation axis and having a measurement surface inclined at a predetermined angle with respect to a plane orthogonal to the rotation axis, a rotation axis driving mechanism for rotating the rotation axis, and a straight line orthogonal to the rotation axis. An axis, an integrated light emitting / receiving laser sensor mounted on the linear axis so that the designed optical axis of the laser light is in parallel with the rotation axis; and A linear axis drive mechanism for moving the jig in the axial direction, wherein the rotation angle of the jig is 0 ° and 180 °. An inclination of an optical axis of the laser light is calculated. 6. An apparatus according to claim 5, wherein said rotary shaft drive mechanism is a servomotor with an encoder. 7. An apparatus for measuring the inclination of an optical axis of a laser beam according to claim 5, wherein said linear axis drive mechanism is a mechanism combining a servomotor with an encoder and a ball screw.