JPH04203907A - Indication fitting for measuring apparatus of position and attitude - Google Patents

Abstract

PURPOSE:To measure the position and attitude of an instruction point correspondingly to the shape of a workpiece and also to enable accurate measurement of the position of a light-emitting body by forming at least three branches on a handle part and also by disposing the light-emitting body at the end part of each branch. CONSTITUTION:In a space shown by axes X, Y and Z, two CCD cameras 3a and 3b are disposed as position detecting means at different positions and an indication fitting 2 having a light-emitting source emitting a light to be sensed by the cameras 3a and 3b is set on a workpiece 1. In this fitting 2, a peak-shaped instruction point 6 is formed in the fore end of a handle part 15 and, moreover, three branches 16a, 16b and 16c shaped in slender columns or the like and having arbitrary lengths and angles are formed of synthetic resin, metal or others integrally with the fitting. Besides, three light-emitting bodies 5a, 5b and 5c are disposed at the end parts of the branches respectively. When the shape of the workpiece and others are measured, various shapes can be dealt with easily according to this constitution, and also by employing light- emitting bodies each having a known luminous intensity distribution for all directions as the above light-emitting bodies, precision can be further improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an indicator for a position and orientation measuring device.

[Prior Art] As a method of measuring the shape etc. of a workpiece, an indicator 2 shown in FIG. 9 is used. The indicator 2 has three light emitters 5a and 5b on a flat plate 30 formed in a planar shape.

5C is used, the pointed end of the indicator 2 is placed on the workpiece, and the position of the light emitter is measured. That is, as shown in FIG. 1, place the indicating tool 2 on the workpiece,
Two light receivers (for example, CCD cameras) 3a and 3b receive images of the light emitters 5a, 5b, and 5c. The positions of the light emitters 5a, 5b%5C are calculated from the angles of the light receivers 3a, 3b when the images are received.

[Problem to be solved by the invention] The above-mentioned indicator 2 is mounted on a flat plate (light-emitting bodies 5a, 5b).

5c are arranged, the relative angle at which the two light receivers 3a, 3b can be installed is determined, and depending on the shape of the workpiece, there may be cases where both light receivers 3a, 3b cannot receive light. In that case, it is necessary to change the installation position of the light receiver 3a13b. Furthermore, since the luminous intensity of the conventional light emitters 5a, 5b, and 5C is not uniform with respect to the light emitting direction, it is difficult to obtain an accurate angle of the light receiver depending on the installation position of the light receiver.

As a result, there is a problem that the position of the light emitter cannot be accurately measured.

Therefore, the present invention provides an indicator for a position/orientation measuring device that solves these problems.

[Means for Solving the Problems] A position that includes an indicator having a light emitter, two or more light receivers that receive light from the light emitter, and an arithmetic device that calculates the position and angle of the light receiver; The pointing device according to claim 1, which is used in a posture measuring device, has at least three branches formed in the handle portion of the pointing device, and a light emitting body is attached to the end of the branch.

The pointing device according to claim 2 is a branch of the pointing device according to claim 1, which is formed to be extendable and contractible.

Further, the indicating device according to claim 3 is a branch of the indicating device according to claim 1, which is formed in a detachable manner.

A fourth aspect of the present invention provides that the light emitting body used in the first to third aspects of the present invention has a known luminous intensity distribution in all directions.

[Operations] The indicator for a position and orientation measuring device according to claim 1 has at least three branches formed in the handle portion, and a light emitting body is attached to the end of the branch. With this indicator, the light receiver can see the light emitters from almost all directions without changing its position, and the position of each light emitter can be measured by receiving images of each light emitter with the receiver and calculating them with a calculation device. I can do it.

Further, in the position/orientation measuring device indicator according to claim 2, the branches are formed to be extendable and contractible so that the position of the light emitting body can be adjusted. Therefore, the position and orientation of the teaching point can be measured according to the shape of the workpiece without changing the position of the light receiver.

In the position/orientation measuring device indicator according to claim 3, the branch attached to the handle is detachably formed. Therefore, by attaching a branch of a predetermined length to the handle, the position of the light emitter can be selected, and the position and orientation of the teaching point can be measured in accordance with the shape of the workpiece.

A fourth aspect of the present invention provides that a light emitter whose luminous intensity has a known luminous intensity distribution in all directions is attached to the branches of claims 1 to 3. By using this light emitter, the position of the light emitter can be measured more accurately because the luminous intensity is known regardless of the position of the light emitter.

[Example] An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a conceptual diagram of measuring the position of a light emitting body 5a using a position/orientation measuring device pointing tool 2 (hereinafter referred to as a pointing tool) of the present invention. That is, X, Y.

In the space represented by the Z axis, two CCD cameras 3a and 3b are disposed at different positions as position detection means, and
FIG. 2 is a diagram in which an indicator 2 having a light emitting source for receiving light by CD cameras 3a and 3b is placed on a workpiece 1. CCD
Each of the cameras 3a, 3b is provided with an adjustment mechanism so that light can be received even if the positions of the light emitters 5a, 5b, 5c are moved significantly. As shown in FIG. 2, the indicating tool 2 placed on the workpiece 1 has a handle 15 with a pointed teaching point 6 formed at the tip thereof, and three thin cylinders of arbitrary length and angle. The branches 16a, 16b, and 16c are integrally formed of synthetic resin, metal, or the like. Also, the branch 16
A, 16b, and 16c are provided with three light emitters 5a at their ends so that their positions and orientations (angles) can also be measured as described later.
, 5b, and 5c are arranged.

Next, a method of measuring the position of the light emitters, the distance between the light emitters, and the angle of the teaching point using the two CCD cameras 3a, 3b and the pointing tool 2 described above will be explained.

First, as shown in FIG.
Place it at the position and posture (angle) to be measured above. Then, the CCD cameras 3a, 3b are connected to the light emitters 5a, '5b, 5c.
Adjust the position to receive the light emitted from the

The positions of the CCD cameras 3a, 3b, etc. in the space represented by the X5YXZ axes are as follows. That is, the position coordinates of the fixed CCD cameras 3a and 3b are Pa (Xa, Y
Pi (X
i, Yl, Zl), P2 (X2.Y2.Z2),
Let P3 (Xa, Y3.Za) and the coordinates of the teaching point 6 of the pointing tool 2 be pt (Xt, Yt, Zt).

(1) Find the coordinates PL (Xi, Yl, Zl) of the light emitter 5a.

The CCD cameras 3a and 3b receive the light from the light emitter 5a, or are adjusted so that they can receive the light.
The zenith angles of a and 3b are α11 and α21, and the horizontal angle is β11.
, β21 is detected (Fig. 1).

The distance between Pa and Pl is Lla, and the distance between Pb and Pl is Ll.
If b, zenith angle α11, α21, horizontal angle β11, β
Regarding 21, X1=Xa −Lla −3IN (all) ・CO3(β11)
Y1=Ya -L1a-8UN (α11)・SIN (β11)
Z1=Za+L1a -CO8(αII)X1=Xb -Llb-8IN(α21)・CO8(β21)Y1
=Yb-Llb-8IN(α21)・5IN(β21)Z1
The relational expression =Zb+L1b-CO3(α21) is established.

From each of the above formulas, the coordinates PI (Xi) of the light emitter 5a.

Yl, Zl) are found.

(2) Next, find the coordinates P2 (X2. Y2°Z2) of the light emitter 5b.

Since it can be obtained in the same manner as in (1) above, illustration is omitted. The obtained zenith angle is α12, α22,
The horizontal angles are β12 and β22, and the distance between Pa and 22 is L
If the distance between 2a, Pb and 22 is L2b, then X2=Xa -L2a -3IN (α12) ・CO8(β1
2) Y2=Ya -L2a -8IN (α12) ・S IN
(β12) Z2=Za+L2a −CO8((lE12
)X2=Xa -L2b-8IN(α22)・CO8(β22)Y2
=Ya -L2b-8IN(α22)・5IN(β22)Z2
The equations =Za+L2b-CO8(α22) are established, and the coordinates P2 (X2°Y2.Z2) of the light emitter 5b are determined.

(3) Furthermore, the light emitter 5c (7) coordinates P3' (Xa, Y3
Find ゜Za).

Similarly to the above, the coordinates P3 of the light emitting body 5C are expressed as α13, α23 for the zenith angles, β13, β23 for the horizontal angles, and Pa
The distance between Pb and 23 is L3a, and the distance between Pb and 23 is L3b.
Then, X3=Xa -L3a-3I N (α13) -CO8(β13)
Y3=Ya −L3a −8I N (α13) ・S IN
(β13) Z3=Za+L3a −CO8(α13
)X3=Xa -L3b-S IN (α23)・CO3(β23
)Y3=Ya -L3b-8IN(α23)・5IN(β23)Z3
=Za+L2b-cos (α23) holds true,
Coordinates P3 (Xa) of the light emitter 5c.

Y3. Za) is found.

(4) Each light emitting body 5a, 5b obtained as above.

Each coordinate point PL (Xi, Yl, Zl) of 5C, P2 (X
2. Y2. Z2), P3 (Xa, Y3.Za), the plane equation passing through each coordinate is as follows.

Next, the direction cosine, M, and N of the above plane are determined.

Here, the cosine of each direction is L=CO8(α), M=CO8(
β), N=CO8(γ), then (X-Xi)/L
= (Y-Yl)/M= (Z-Zl)/N (X-X2)/L= (Y-Y2)/M= (Z-22
)/N (X-X3)/L= (Y-Y3)/M= (Z-23
)/N holds true, and from each of the above equations, the direction cosine.

Find M and N. That is, by measuring the positions of three different light emitters, the angle passing through the light emitters can be determined.

(5) Next, determine the coordinates Pt, that is, the coordinates pt (xt, yt, zB) of the placement point on the workpiece 1.

When the plane of the coordinates P1 and P2 and the plane containing the coordinate point pt are the same, the coordinate point pt is the coordinate P whose positional relationship is known.
1, P2 or P3.

However, the plane of coordinates P1, P2, P3 and the coordinate point P
In the case of the indicator 2 in which the surface including t (teaching point) is formed at an arbitrary known angle (α′, β゛, γ°),
The direction cosines L1M and N obtained above are angularly corrected to obtain L', M', and N'.

□ The indicator 2 used in this example has branches 16a and 16b.
, 16c, the light emitters 5a, 5b, 5c are attached to the tips of the light receivers, so that measurements can be made without rotating the indicator, that is, regardless of the position of the light receiver as long as it is not blocked by the workpiece 1. In addition, the indicator in this example has three branches, but by increasing the number of branches, the receiver can select and measure any light emitter, making it compatible with various workpiece shapes. can. Further, the angle at which the branch is attached to the handle may be determined by assuming the position of the light receiver that can receive the light emitting body, and may be formed, for example, as shown in FIG. 3.

That is, FIG. 3(a) shows a front view, and FIG. 3(b) shows a plan view, and the branches 16a, 16b, and 15c have different lengths and are formed at an angle of 120° on the plane. The light emitter can be received from almost any position on the receiver.

Next, FIG. 4 corresponds to claim 2, and branches 16a, 16b, and 16c are formed to be expandable and contractible. That is, the handle part 15 has support parts 18 a, 18 b, 18 c having screws 20 formed in arbitrary directions, and branches 16 a, 16 b, which mesh with the screws 20.
16c is attached.

By rotating the branches 16a, 16b, 16c, the positions of the light emitters 5a, 5b, 5c can be changed, so that measurements can be made in accordance with the shape of the workpiece.

Incidentally, as shown in FIG. 5, the branch is divided into many parts, and each divided branch 22a, 22. b, 22c may be formed to be slidable and extendable.

FIG. 6 corresponds to claim 3, and shows that the handle portion 15 has a large number of support portions 18a118b, 18c in each direction.
A long hole 21 is bored in the hole. Branches 16 of different lengths are prepared in advance so that they can be fitted and inserted into the elongated hole 21, and the branches 16 of appropriate lengths are placed at positions corresponding to the shape of the workpiece.
Insert.

Since the position of the light emitter can be selected by the branch 16 for insertion and attachment, it is possible to correspond to various workpiece shapes.

FIG. 7 is a diagram showing an image receiving screen 11 on a light receiver using a light emitter having a Gaussian distribution, with the luminous intensity of the light emitter having a known luminous intensity distribution in all directions.

That is, the image receiving screen 11 of the light receivers 2a and 2b (CCD camera) has pixels 10 arranged vertically and horizontally (the length is a by vertical and horizontal by b).
The center of the image receiving screen 11 of the light receivers 3a and 3b (
The photoreceiver 3a
, 3b.

However, depending on the type of light emitting body 5, the image may be received across a plurality of pixels 10 as shown in the shaded area in FIG. becomes unclear, and it is difficult to measure the position of the light emitter 5 with an accuracy less than the length of the pixel 10. That is, since the luminous intensity distribution of the light emitter 5 is unknown,
The light intensity distribution on the image receiving screen 11 differs because the positions and angles of the light receivers 3a and 3b differ. Therefore, even if the angles of the light receivers 2a and 2b are adjusted so that the light is received at the center of the image receiving screen 11 (the intersection of the pixels indicated by the line mSn), the angles are inaccurate.

However, when using a light emitter 5 that emits light in a Gaussian distribution that is known in all directions, the received light intensity also peaks at the center mXn of the image receiving screen 11, as shown in FIG. It becomes a Gaussian distribution with
, 3b are received regardless of their positions and angles. Therefore, the angle (
Zenith angle α11, α21. The horizontal angles β11, β21) are detected, and the position P1 of the light emitter 5 is determined by the arithmetic processing unit in the manner described above.
seek.

In this way, if a light emitter having a Gaussian distribution is used in all directions, the light receivers 2a and 2b can be used regardless of the position of the receiver.
Accurate angles can be measured. As a result, the position and orientation (angle) of the determined teaching point can be measured accurately, that is, with an accuracy equal to or less than the length of the pixel 10.

Furthermore, by attaching a light emitter having a Gaussian distribution in all directions to the various types of indicators described above, it is possible to accurately and easily handle workpieces of various shapes without changing the position of the light receiver. I can do it.

[Effects of the Invention] According to the pointing tool for a position and orientation measuring device of the present invention, when measuring the shape of a workpiece, simply holding the pointing tool in your hand and setting it at the desired position and orientation moves the light receiver. Without a problem,
Can easily accommodate various workpiece shapes. Furthermore, if a light emitter having a known luminous intensity distribution in all directions is used as the light emitter, accuracy can be further improved.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a conceptual diagram for measuring the position of a light emitting body, FIG. 2 is a front view of an indicator corresponding to claim 1, and FIG. 4.5 is a side sectional view of the indicating device corresponding to claim 2, and FIG. 6 is a front view, FIG. 4.5 is a front view, and FIG. A side sectional view of the indicator corresponding to item 3, Fig. 7 is a diagram of the image receiving screen of the light receiver, Fig. 8 is a diagram showing the received light intensity distribution of the light receiver, and Fig. 9 is a front view of the conventional indicator. be. 1... Workpiece 2... Indicator 3a, : 3b - CCD camera Pa, Pb... Coordinates of CCD camera 5 a, 5 b, 5 c--- Light emitters P1, P2,
Pa...Coordinates of the position detector pt...Teaching points α11, α21... ...Zenith angle β11, β21... ...Horizontal angle

Claims (4)

[Claims] (1) In a position and attitude measuring device that has an indicator having a light emitter, two or more light receivers that receive light from the light emitter, and an arithmetic device that calculates the position and angle of the light receiver. , forming at least three branches on the handle of the indicator,
An indicator for a position and orientation measuring device, characterized in that a light emitting body is attached to the end of the branch. (2) The indicator for a position and orientation measuring device according to claim 1, characterized in that the branch of the indicator is extendable and retractable. (3) The indicator for a position and orientation measuring device according to claim 1, characterized in that the indicator is formed with detachable branches. (4) Claims 1 and 2, characterized in that the luminous body has a known luminous intensity distribution in all directions.
Item 3. Indicator for position and posture measuring device.