JPS6197504A - 3-d position measurement - Google Patents

Abstract

PURPOSE:To enable a highly accurate measurement, by measuring coordinate positions of a probe within a specified coordinate plane with a laser length measuring device from an external fixed point while those are measured along the axis of coordinate crossing the specified coordinate plane. CONSTITUTION:A measuring device 1 has a table 2 for placing an object to be measured thereon and a girder 3 is so arranged to be freely driven to move in the X-axis way while a head 5 to be done so in the Y-axis way at the right angle to the X axis. A spindle 6 having a probe 7 at the tip thereof is provided on the head 5 in such a manner to be freely driving to move in the Z-axis way at the right angle to the X and Y axes. Then, coordinate positions of the probe 7 within a specified coordinate plane such as X-Y plane are measured from an external fixed point using triangulation with laser length devices 10 and 11 while those along the axis Z of coordinate crossing a specified coordinate plane X-Y are measured with a laser length measuring device 12 from the external fixed point likewise to compute coordinate positions in X, Y and Z coordinate spaces of the probe 7 with a distance computing section.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention is applied to a three-dimensional measuring device that measures the coordinate position of a predetermined point on an object to be measured using a laser beam. Regarding.

(b), Prior Art FIG. 10 is a perspective view showing an example of a three-dimensional measuring device using a conventional three-dimensional position measuring method.

Conventionally, in this type of three-dimensional measuring device 1, as shown in FIG. 10, a gutter 3 is provided on a table 2 so as to be movable in the X-axis direction, and a head 5 is mounted on the gutter 3 in a manner that the head 5 is aligned along the X-axis. It is provided so as to be movable in the Y-axis direction perpendicular to . Also,
The head 5 is provided with a spindle 6 having a probe 7 attached to its tip so as to be movable in the Z-axis direction, which is perpendicular to the x- and Y-axes. table 2, garter 3, head 5
, each of the gutter 3, head 5, and spindle 6
Measuring means such as a linear scale 9 for measuring the amount of displacement of the axis, Y axis, and Z axis is provided, and the probe 7
The coordinate position in the three-dimensional space was determined by measuring the amount of movement of the gutter 3, head 5, and spindle 6, which support and move the probe 7, using a linear scale 9.

(C) 0 Problems to be Solved by the Invention However, in such a structure, each linear scale 9 is moved in the X-axis direction of the gutter 3, in the Y-axis direction of the head 5, and in the Z-axis direction of the spindle 6.
The amount of movement in the axial direction is measured and the coordinates of the probe 7 are indirectly calculated, and the measured values are transmitted to the gutter 3, head 5,
It is affected by mechanical properties such as thermal displacement occurring in the spindle 6, perpendicularity of each component in assembly, and deviations in straightness with respect to each coordinate axis. Therefore, considerable errors and variations in measured values occur between the actual position of the probe 7 and the measured position of the probe 7, making it impossible to achieve measurement accuracy exceeding the mechanical properties.

In order to eliminate the above-mentioned drawbacks, the present invention makes it possible to perform measurements in a manner that eliminates the effects of thermal displacement, perpendicularity in assembly of each component, and deviations in straightness with respect to each coordinate axis, and improves mechanical properties. It is an object of the present invention to provide a three-dimensional position measuring method that allows highly accurate measurement without being influenced by other factors.

(d) Means for solving the zero problem, that is, the present invention measures the coordinate position of the probe in a specific coordinate plane from a fixed external fixed point using a laser length measuring device using triangulation method. , the coordinate position of the probe along the coordinate axis intersecting the specific coordinate plane,
Similarly, the coordinate position of the probe in three-dimensional space is determined by measuring with a laser length measuring device from a fixed external fixed point.

(e) 0 effect With the above configuration, the present invention allows the position of the probe to be directly measured by a laser length measuring device within a specific coordinate plane,
Furthermore, the coordinate position of the probe related to the coordinate axis intersecting the coordinate plane is directly measured by a laser length measuring device, and the coordinate position of the probe in three-dimensional space is influenced by the characteristics of the mechanical system that supports and drives the probe. It acts so that it can be measured without being affected.

(f), Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a perspective view showing an example of a three-dimensional measuring device to which an embodiment of the three-dimensional position measuring method according to the present invention is applied, and FIG. 2 is a perspective view showing a measurement optical system in the three-dimensional measuring device of FIG. Figure 3 is a perspective view showing the correction optical system in the three-dimensional measuring device of Figure 1, Figure 4 is an enlarged view of the vicinity of the spindle,
5 is a control block diagram of the drive system in the three-dimensional measuring device shown in FIG. 1, FIG. 6 is a control block diagram of the optical system in the three-dimensional measuring device shown in FIG. 1, and FIG. 7 is a control block diagram of the optical system in the three-dimensional measuring device shown in FIG. A plan view showing an example, Fig. 8 is a front view of Fig. 7, and Fig. 9 is a front view of Fig. 7.
The figure is a diagram showing a method for correcting shake in each axis.

As shown in FIG. 1, the three-dimensional measuring device 1 includes a table 2 on which an object to be measured is placed, and a guide rail 2a is installed on the table 2 in the X-axis direction. A gutter 3 is provided on the guide rail 2a so as to be movable and driven in the X-axis direction, and a head 5 is mounted on the gutter 3 in a Y direction perpendicular to the X-axis.
It is provided so that it can be freely moved and driven in the axial direction. The head 5 is provided with a spindle 6 having a probe 7 attached to its tip so as to be movable in the Z-axis direction perpendicular to the X-axis and the Y-axis.

Next, the optical system N1 in the three-dimensional space will be explained.

The three-dimensional measurement device 1 includes a measurement optical system OMS and a correction optical system OA.
As shown in Fig. 6, the measuring optical system OMS has three laser length measuring units @10, 11, and 12, and the laser length measuring device 10°, 11, and 12 is An oscillator 13 is installed to freely supply a laser beam 15 to a beam splitter 10a of the length measuring device 10. Each length measuring device 10.11.12 has a beam splitter lOa, 11a, 12a
are provided, and beam splitters 10a, 11a,
Interferometers 10b and 12a are interferometers 10b and llb, respectively.

Corner cubes 10c, 11c, 12c, which are retroreflectors, are provided via 12b.

In addition, each length measuring device 10, 11, 12 has a receiver 10d1.
A lid, 12g is provided. Furthermore, a correction optical system OAS is connected to the measurement optical system OMS, and the correction optical system OAS includes a deflection measuring device 16 that measures the deflection of the spindle 6 in the Y-Z plane, and a deflection measuring device 16 that measures the deflection of the spindle 6 in the Z-X plane. A runout measuring bag W117 for measuring the runout of 6 and a positional shift measuring device 19 for measuring the positional shift in the Z-axis direction are provided.

Each shake measuring device 16, 17 and positional deviation measuring device 19 are provided with photodiodes 16b, 17b, 19b via condensing lenses 16a, 17a, 19a, and each photodiode 16b, 17b, 19b An amplifier 20 is connected to each. A main control section 22 is connected to the amplifier 20 via a correction amount calculation section 21, and a display control section 23 and a probe control section 2 are connected to the main control section 22.
5. A laser control unit 26 and the like are connected. Display control section 2
A display 27 is connected to the probe controller 25.
A probe 7 is connected to the probe 7 , and a laser oscillator 13 is further connected to the laser control section 26 . On the other hand, a distance calculation section 29 is connected to each receiver 10d11id, 12g of the measurement optical system OMS, and the distance calculation section 29 is connected to the above-mentioned main control section 22.
is connected.

Next, the drive control system in the three-dimensional measuring device 1 will be explained. As shown in FIG. 5, the main control section 22 described above includes:
A drive control unit 30 is connected to the drive control unit 30.
A moving direction indicating means 32 such as a joystick lever is connected via a /D converter 31 . In addition, the drive control section 30
A pulse distributor 33, 35 and a pulse generator 36 are connected to the pulse distributor 33 and pulse generator 36.
Pulse motors 39, 40, 41 for driving the X, Y, and Z axes are connected via three drive circuits 37 to.

Note that when the pulse motor 39 is driven, the ball screw 42
When the pulse motor 40 is driven, the head 5 is moved through the ball screw 43.
is driven to move in the Y-axis direction, and when the pulse motor 41 is further driven, the spindle 6 is driven to move in the Z-axis direction via the ball screw 45.

The pulse distributor 35 also has four mirror drive pulse motors 47, 49, 50,
51 is connected and ``Lusumo 1-ta 4
7 has a corner cube llc, as shown in Figure 2,
It is provided rotatably within the X-Y plane. The pulse motor 49 includes a corner cube 10C and, as shown in FIG. 2, a reflecting mirror 1211 among three reflecting mirrors 12 d, 12 e, and 12 f provided between the interferometer 12 b and the beam splitter 12 a. Furthermore, a reflecting mirror 52 of the correction optical system 0'AS is provided coaxially and rotatably within the XY plane. Note that these pulse motors 47 and 49 are housed in the head 5 that moves in the Y-axis direction. The pulse motor 50 also includes an interferometer 11 as shown in FIG.
Reflector lie installed between b and corner cube lie
is provided rotatably in the X-Y plane, and the pulse motor 51 has a reflection mirror 10e1 provided between the interferometer 10b and the corner cube 10c, the reflection mirror 12d mentioned above, and the correction optical system 0-As. A mirror 53 is provided coaxially and rotatably within the XY plane. Note that these pulse motors 50 and 51 are provided at an external fixed point SP that is independent of the movable gutter 3 and the head 5.

Here, the arrangement of each reflecting mirror, corner cube, etc. in the measurement optical system OMS and the correction optical system OAS will be explained. As shown in FIG.
a beam splitter 10a for transmitting and reflecting 5;
11 all 2a is provided, and an interferometer 1
0b,llb.

Receiver 10d, lid, and the above-mentioned pulse motor 50
．． 51 is provided together with a reflecting mirror. Further, on the head 5 that moves in the Y-axis direction (including the spindle 6 attached to the head 5; the same applies hereinafter), the above-mentioned pulse motor 4 is mounted.
7.49 is provided together with a corner cube, a reflecting mirror, etc., and an interferometer 12b1 constituting the laser length measuring device 12 is also provided.
Corner cube 12c/Reba 1261 reflector 12f
etc. are provided.

Further, as shown in FIG. 3, the correction optical system OAS includes a reflecting mirror 5 provided together with a pulse motor 51 at an external fixed point SP.
3, a reflector 52 mounted on a pulse motor 49 on the head 5, and two beam splitters 55.
A deflection measuring device 16, 17 and a positional deviation measuring device 19 are provided via the beam splitter 55, 56, and the positional relationship of each component therein is as shown in FIG. The runout measurement value w16.17 is provided on a bracket 6a provided on the spindle 6. Further, the bracket 5a includes a positional deviation measuring device 19 and an interferometer 12.
b is also provided, and the bracket 6a is further provided with a corner cube 12c.

Since the three-dimensional measuring device 1 has the above configuration, when measuring the coordinates of a specific point on the object to be measured placed on the table 2, as shown in FIG. Preview 7 by operating the movement direction indicating means 3 and 2
is moved and driven in appropriate directions of the XSY and Z axes. That is, by operating the moving direction indicating means 32, the moving direction of the probe 7 is instructed to the drive control unit 30 via the A/D conversion @31, so the drive control unit 30 controls the pulse distributor 33.
and instructs the pulse generator 36 to distribute and output appropriate drive pulses DP in the direction instructed by the movement direction instructing means 32, and the pulse distributor 33 and pulse generator 36 receive this and instruct the respective drive circuits 37. Outputs drive pulse DP. Each drive circuit 37 rotates each pulse motor 39, 40, 41 according to the amount of the drive pulse DP, and rotates the ball screw 42.
43. The gutter 3, head 5 and spindle 6 are moved in the x, y and z axes directions through the shafts 43 and 45, respectively. Then,
The probe 7 attached to the tip of the spindle 6 also has XSY, Z
It moves in the axial direction and gradually approaches the measurement point of the object to be measured. In this way, when the moving probe 7 contacts the fixed point of the object to be measured, the signal S1 is outputted from the probe 7 to the main control section 22 via the probe control section 25, and the main control section 22 outputs the signal S1 to the main control section 22. and instructs the correction amount calculation section 21 to calculate the coordinate values of the probe 7.

Here, the three-dimensional measuring device i! The first measurement method will be explained. First, as shown in FIG. 6, the main controller 22 drives the laser oscillator 13 via the laser controller 26, and emits the laser beam 15 from the laser oscillator 13 to the beam splitter 10a of the laser length measuring device 10. . The laser light weight 5 is partially transmitted by the beam splitter 10a.
a and enters the interferometer 10b, where it is separated into measurement light and reference light.
The light enters the corner cube 10c via the angle e, where it is reflected to the reflecting mirror 10e at the same angle of incidence and enters the interferometer 10b again. In the interferometer iob, interference fringes are generated by interfering the measurement light and the reference light that are incident again, and the interference fringes are received by the receiver 10d, and the distance calculating section 29 calculates the interferometer 1.
A distance LL1 from 0b to the corner cube 10c is calculated.

Regarding the distance measurement method using the laser length measuring device 10, etc.,
Many products are already on the market, and the three-dimensional measuring device 1 according to the present invention can also utilize such a known laser length measuring device, so only an outline thereof will be described here and a detailed explanation will be omitted.

Further, a part of the laser beam 15 is reflected by the beam splitter 10a and enters the beam splitter lla, and the distance fiLL2 between the interferometer 11b, the reflecting mirror 11e, and the corner cube llc is measured by the laser length measuring device 11. Note that the laser beam 15 enters the corner cubes 10c, llc provided on the moving head 5 from the external fixed point SP, and further enters the interferometers 10b, llb of the external fixed point SP; Pulse motor 4
9.47, the pulse motor 51.50 that drives the reflecting mirrors 10e and
The laser beam 15 is controlled so that the optical axis of the laser beam 15 is constant according to the driving amount of the pulse motors 39 and 40 of the X and Y axes by the 4m section 30.
Despite the movement of the gutter 3 in the Y1X direction, the light is received and reflected at certain points on the corner cubes 10c and llc.
, LL2 can be measured.

As shown in FIGS. 7 and 8, the laser length measuring device 10.11 measures and calculates the coordinate position of the probe 7 in the X-Y plane, but the measurement calculation at this time is based on the triangulation method. Be done. That is, the distance in the X-axis direction from the attachment point PXY of the probe 7 in the X-Y plane to the corner cube 10c, lie is P4, as shown in FIG. The distance in the axial direction is P5, and the distance in the Y-axis direction from corner cube 10c to corner cube llc is P2 and 1, (co-t
*5-) 10c and 11c are assumed to be on the fQl-XFj5 mark. ), and a reflecting mirror 10e.

The distance in the Y-axis direction between the reflector 10e and the corner cube 10c is 11, the distance between the reflector lie and the corner cube llc is 12, and the reflection i+H
Triangle A whose base is the distance between oes lie $11P1
Consider DE. Further, if the distance in the Y-axis direction between the reflecting mirror 10e and the interferometer 11b is P3 as shown in FIG. P3 12=LL2-Pi-P3 Since ΔADE and ΔABC are similar, AB=α, AC
= β, a=P2 ・j 1/ (Pi−P2)β=P2・t
2/ (PL-p2) This gives the length of each side of ΔADE, and the angle AD
Assuming E-tension θ, then the coordinate position x, y of point B of the corner cube 10c, based on the origin of the X-Y coordinates where the reflecting mirror 10e is placed, is x=11 ・sin θ y== 11-eosθ Therefore, the coordinates of the attachment point PXY of the probe 7 are X', y'
Then, X' = l 1 ・sin θ + P 4
-=(11y' = 11 ・cose+ps
...=(21.

Note that the laser beam 15 transmitted through the beam splitter lla
is incident on the beam splitter 12a, where a part of the laser beam 15 is incident on the laser length measuring device 12, and as shown in FIG.
A reflecting mirror 12e11 provided on the head 5 moving in the direction
2f, and further an interferometer 12 provided on the bracket 5a.
The spindle 6 is driven to move in the Z-axis direction via b.
Corner cube 1 attached via bracket 6a to
2c, is received by the receiver 12g, and the distance gi in the two axial directions between the interferometer 12b and the corner cube 12c is
Measure LL3. Now, assuming that the position of the interferometer 12b is the origin in the Z-axis direction, the Z coordinate 2' of the probe 7 is z' = LL3 + P6 = j 3
......(3) (P6 is corner cube 1
2c and the distance in the Z-axis direction from the center of the probe 7).

In this way, the coordinate positions X'', Y', and z' of the probe 7 in the X1Y, Z coordinate space are calculated by the distance calculating section 29 from equations (1), (2), and (3). performs a correction operation on these calculated values.

That is, due to the movement of the movable part, the gutter 3 undergoes slight vertical displacement and collapse, and the vertical movement of the spindle 6 causes z-x,
Measure the runout, etc. in the y-z plane, and from that value (1)
, (2), correct the coordinate position of the probe 7 determined by equations (3) (the distance measured by the laser length measurement 910, 11.12 is not the distance to the probe 7 itself, but the distance to the probe 7 Since the coordinates are located at predetermined distances P4, P5, and P6, the gutter 3, head 5, and spindle 6
There is a possibility that the actual coordinate position of the probe 7 may deviate from the coordinate position calculated by the laser length measuring device 10.11.12 due to vibration or the like. ).

That is, as shown in FIG. 6, the laser beam 15 transmitted through the beam splitter 12m is transmitted through the beam splitter S5.56.
Runout measuring device 16,17 and positional deviation measuring device 1
9 and the condenser lenses 16 a, 17 all 9
a to each photodiode 16b, 17b, 19
incident on b. Photo 7 diode 16b117b
As shown in FIG. 4, is provided on the bracket 6a of the spindle 6 on which the probe 7 is attached, and the laser beam 15 is transmitted from the external fixed point SP to the reflecting mirrors 57, 53, The beam enters the beam splitter 55.56 via the reflecting mirror 52 of the head 5, and part of the beam enters the photodiode 16b having measurement directionality in the Y direction, and the other part of the beam enters the X
Photodiode 1 with measurement directionality in the direction? incident on b. In addition, the remaining laser beam 15 is transmitted through the bracket s
The light is incident on the photodiode 19b of the positional deviation measuring device 19 provided on the top a, which has measurement directionality in the Z direction. The correction and calculation section 21 includes each photodiode 16b11.
From the outputs of 7b and 19b, as shown in FIG. 9, correction values ε8, ε2, and ε2 for the mounting position PxYZ of the probe 7 in the three-dimensional space are determined and output to the main controller 22. The main control unit 22 outputs the correction values ε, ε2, ε2 and the coordinate values x', y' of the probe 7 output from the distance calculation unit 29.
, z', the assembly error inherent to each three-dimensional measuring device 1, the machine-specific correction values α, α, such as the flatness of the table 2, etc.
, α, the corrected coordinate value xS of the probe 7
y, z (displacement angle γ mound 2" in the Z-axis direction in Fig. 9)
At the level of Renote, eos7 arm 1 Toshi T, z-x, y
The influence of shaking in the −z plane on the Z coordinate value is ignored. )x= 11 ・sinθ+P4±ε+αY=j
1 ・cosθ+P5±ε+αZ=13±ε10 (select according to measurement point and direction of movement).

Note that each of the reflecting mirrors 53 and 52 of the correction optical system OAS is also
As shown in the figure, the pulse motor 51.49 rotates the optical axis of the laser beam 15 so that it does not change with respect to the beam splitter 55.56 in conjunction with the movement of the gutter 3 and head 5 in the X and Y directions. Since it is driven, it is possible to always calculate appropriate correction values ε8, ε2, and ε2.

Note that the coordinate values X, Y, and Z of the probe 7 calculated by the main control section 22 are displayed on the display 27 via the display control section 23.

In addition, in the above embodiment, the mounting position of the probe 7 in the x-y plane is determined by triangulation to determine the lengths of the three sides of the reference ΔADE, and from that, the angle θ is determined. However, the coordinate position of probe 7 may be determined by any method as long as it is determined by triangulation.
The length of one side and the angles at both ends are the conditions for determining a triangle.
Of course, it is also possible to determine a reference triangle by measuring the lengths of two sides and its included angle, and calculate the coordinate position based on this.

(g) 0 Effects of the Invention As explained above, according to the present invention, the coordinate position of the probe 7 within a specific coordinate plane such as the X-Y plane is determined by the triangulation method using the laser length measuring device 10.11. The laser length measuring device 12 measures the coordinate position of the probe along a coordinate axis such as the Z-axis that intersects with the specific coordinate plane from a similarly fixed external fixed point SP. Since the coordinate position of the probe 7 in three-dimensional space is determined by measuring the
It is possible to directly measure the coordinate position of the block 7 during the cubic intersection 1, and the x, y position of the gutter 3, head 5 and spindle 6 can be directly measured.
This makes it possible to perform measurements that eliminate the effects of thermal displacement, perpendicularity during assembly of each component, and deviations in straightness with respect to each coordinate axis, which were observed when measuring the amount of movement in the Sz-axis direction. Highly accurate measurement is possible without being influenced by the mechanical characteristics of the measuring device 1.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a three-dimensional measuring device to which an embodiment of the three-dimensional position measuring method according to the present invention is applied, and FIG. 2 is a perspective view showing a measurement optical system in the three-dimensional measuring device of FIG. Figure 3 is a perspective view showing the correction optical system in the three-dimensional measuring device of Figure 1, Figure 4 is an enlarged view of the vicinity of the spindle,
5 is a control block diagram of the drive system in the three-dimensional measuring device shown in FIG. 1, FIG. 6 is a control block diagram of the optical system in the three-dimensional measuring device shown in FIG. 1, and FIG. 7 is a control block diagram of the optical system in the three-dimensional measuring device shown in FIG. A plan view showing an example, Fig. 8 is a front view of Fig. 7, and Fig. 9 is a front view of Fig. 7.
The figure shows a method for correcting shake of each axis, and FIG. 10 is a perspective view showing an example of a conventional three-dimensional measuring device. 1...Three-dimensional measuring device 3...Moving mechanism (garter) 5...Moving mechanism (head) 6...Moving mechanism (spindle) 7... B4-B10.11.12...Laser length measurement bud sp...
Outside fixed point applicant Debata Iron Works Co., Ltd. Agent Patent attorney Phase 1) Shinji (and 1 other person)

Claims (1)

[Scope of Claims] A three-dimensional measuring device in which a probe is driven to move freely in a three-dimensional space by a moving mechanism, and the probe measures the coordinate position of a specific point on an object to be measured. The coordinate position of the probe is measured from a fixed external fixed point using a triangulation method with a laser length measuring device, and the radiation source position of the probe along the coordinate axis intersecting the specific coordinate/plane is similarly determined. A three-dimensional position measuring method configured to determine the coordinate position of a probe in three-dimensional space by measuring from a fixed external point using a laser length measuring device.