JP2000111314A - Reception light quantity stabilizer for laser type position locating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exactly detect a position by effectively adjusting light quantity in laser type position locating device according to the attenuation of laser light. SOLUTION: A reception light quantity stabilizer 60 for a laser type position locating device has a circular glass substrate 61 and a rotation motor 63 rotating the substrate around an axis by forming chromium evaporation part 67a to 67l with intervals along the periphery of the glass substrate 61 to form ND (neutral density) filter separated in a plurality, and varies step by step the light transmittance of a plurality of ND filters which laser light for position location transmits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser length measuring device for locating a remotely operated movable robot, and more particularly to a light receiving amount stabilizing device for a laser type position locating device.

[0002]

2. Description of the Related Art The use of remotely controlled robots has been proposed for working in places where humans are difficult to access.
FIG. 6 conceptually shows the state of the robot 1 moving in the containment vessel of the pressurized water reactor. Since such a robot 1 works while moving, it is necessary to accurately measure its position, and a three-dimensional position is located as follows. That is, the laser light 5 emitted from the sensor head 3 provided at a position far away from the robot 1 is reflected on the reflecting mirror 7 of the robot 1, and the reflected laser light 5 returns to the sensor head 3 to determine the position. More specifically, the sensor head 3 is attached to the vertical drive shaft 9 and the turning drive shaft 11, and tracks the reflecting mirror 7 to control its azimuth, elevation, distance, and the like.
That is, the three-dimensional position is measured. And the sensor head 3
The control device 13 controls the vertical drive shaft 9 and the turning drive shaft 11 and the drive unit in the sensor head 3, the measuring device 15 measures the angle and the distance, and the calculator 17 performs related calculations. Are electrically connected.

In this way, the position of the robot 1 is
The optical configuration for the measurement is shown in FIG. In the figure, a laser beam emitted from a laser oscillation device 21 passes through an optical fiber 23 and reaches a lens 25, where it is converted into a parallel laser beam 5,
The light is transmitted to the mirror 7 and emitted to the reflecting mirror 7. The laser light 5 reflected by the reflecting mirror 7 enters the light receiving element 31 through the mirror 27 and the lens 29, and further enters the distance measuring device 35 through the amplifier 33. The above-mentioned laser beam before emission is also received by the light receiving element
7, the distance is measured from the return time of the laser beam 5, and the distance is output.

In order to determine the relative angular relationship between the reflecting mirror 7 and the sensor head 3, that is, the azimuth angle and the elevation angle, first, as coarse alignment, the light is polarized by the semi-reflecting mirrors 27 and 39, and then the reflecting mirror 7 is rotated. Is captured by the CCD camera 41, and the vertical axis driving shaft 9 is moved so that the reflecting mirror 7 comes near the center of the image (screen).
And the turning drive shaft 11 is adjusted and driven. Next, in order to perform accurate positioning, the laser beam 5 split (branched) by the mirror 39 is received by the position detection sensor 45 via the lens 43, and the laser beam position is measured on the laser position detection device 47. Meanwhile, the vertical drive shaft 9 and the turning drive shaft 11 are finely adjusted to perform alignment. An azimuth angle and an elevation angle are obtained from the angles of the vertical drive shaft 9 and the turning drive shaft 11 at the time of completion of the alignment. Since the angle and distance obtained in this way correspond to so-called spherical coordinates, the robot 1
Are calculated.

[0005] The basic structure of a conventional position-measuring length-measuring device using a laser is as described above. However, when the robot 1 is underwater and the optical path of the laser light 5 passes through the water, the laser light 5 becomes large. In some cases, the amount of reflected light is insufficient and the amount of reflected return light is insufficient, so that an appropriate measurement result cannot be obtained. Further, if the sensitivity of the light receiving element 31 is set high in consideration of the amount of attenuation, another problem occurs that the light receiving element 31 is saturated when the amount of attenuation in the optical path is small. To deal with such a problem, FIG.
In the sensor head 3, an ND filter (neutraldensity filter) 49 for attenuating the amount of light and a motor 51 for controlling the rotation of the ND filter 49 are attached between the light projecting lens 25 and the mirror 27 in the sensor head 3, as shown in FIG. The output is monitored, and the amount of light received at this portion is stabilized (stabilized). FIG. 9 shows the structure of the ND filter 49 and the motor 51 more specifically. That is, the circular ND filter 49 has a density corresponding to the rotation angle, and the rotation angle is controlled by the motor 51 so as to obtain an appropriate density.

[0006]

The above-mentioned ND filter 4
As shown in FIG. 10A, the attenuation (transmittance) characteristic of the laser light of No. 9 is such that the transmittance changes steplessly with respect to the rotation angle. However, when the amount of received light is adjusted using the ND filter 49, the light amount distribution in the laser light beam before transmission becomes a bilaterally symmetric Gaussian distribution as shown in FIG. The light amount distribution in the laser light beam after the above becomes asymmetrical distribution as shown in FIG. Thus, the above-described position detection sensor 45 uses a four-divided photo sensor 53 as shown in FIG. 11 and outputs X, X and X, respectively, as a, b, c, and d.
The coordinate value and the Y coordinate value are obtained by the following equations. X-coordinate value = {(a + b)-(c + d)} / (a + b + c + d) Y-coordinate value = {(b + d)-(a + c)} / (a + b + c + d) If used, there is no effect on the distance measurement, but it will have an adverse effect on the position measurement. To cope with this problem, a plurality of circular ND filters having an outer diameter larger than the outer diameter of the laser beam and having uniform transmittance over the entire surface are prepared, and these are arranged on the rotating disk in the circumferential direction. There has been proposed the use of an ND filter for attenuation adjustment, which is configured by embedding with a. However, in such an ND filter having a built-in structure, a variation in mounting accuracy of each filter is unavoidable, and a difference in refractive index occurs due to the inclination of the filter plate, which also causes a measurement error in position detection. . Therefore, the present invention provides a method for moving objects using a laser.
It is an object of the present invention to provide a light receiving amount stabilizing device in which a position detection error does not occur in a three-dimensional position locating device.

[0007]

According to the present invention, in order to achieve the above object, according to the present invention, a light receiving amount stabilizing apparatus for a laser type position locating apparatus comprises a circular glass substrate and a glass substrate rotated around an axis. A plurality of separated ND filters formed by depositing a chromium film at intervals along the outer periphery of the glass substrate, and the plurality of ND filters through which a laser beam for position location is transmitted. The light transmittance of the filter is changed stepwise.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, referring to FIG. 1 and FIG. 2, the light-receiving amount stabilizing device 60 includes a circular glass substrate 61, a rotation motor 63 having an output shaft connected to a central shaft thereof, and a mount 65 for supporting the whole. ing.
Then, chromium vapor deposition sections 67a to 67l are formed corresponding to the portions through which the laser beam for position location passes. The relationship between the chromium deposition section 67a and the glass substrate 61 is as shown in FIG. 3, and the thickness of the chromium film deposited on the chromium deposition sections 67a to 67l is sequentially changed stepwise. In this case, the transmittance when the laser beam 69 passes differs. That is,
The chromium deposition sections 67a to 67l form ND filters, respectively. Such chromium deposition sections 67a to 67
In order to form l, a jig or a metal mask plate 71 as shown in FIGS. 4 and 5 may be attached to the glass substrate 61 and chromium deposition may be performed. That is, the metal mask plate 71 has a window 73 corresponding to the size of the chromium vapor deposition sections 67a to 67l. By exposing the glass substrate 61 covered with this to the vapor deposition atmosphere, the chromium vapor deposition sections 67a
~ 67l are formed. Such a chromium deposition section 67a
６７67l have different thicknesses of deposited chromium, but in one chrome deposited portion 67a, since the thickness is uniform over the entire surface, the light quantity distribution after transmission is also a symmetric Gaussian distribution. Therefore, even if this is introduced into the position detecting sensor for position locating, accurate position can be measured.

[0009]

As described above, according to the present invention,
Since a filter is formed by forming a plurality of chromium vapor-deposited sections with different film thicknesses on a single circular glass substrate, the attenuation of laser light can be adjusted without causing fluctuations in the refractive index or asymmetry in the light quantity distribution due to manufacturing errors. Can be stabilized.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a side view of the embodiment.

FIG. 3 is a partially enlarged sectional view showing a main part of the embodiment.

FIG. 4 is a front view of a jig used for manufacturing the glass substrate of the embodiment.

FIG. 5 is a sectional view of the jig.

FIG. 6 is a conceptual diagram of a laser type position locating device in which the device according to the present invention is used.

FIG. 7 is a basic diagram of an optical path configuration of the laser type position locating device.

FIG. 8 is a partial system diagram showing an optical path configuration of a conventional laser type position locating device.

FIG. 9 is an external view of a conventional light reception amount stabilizing device.

FIG. 10 is a diagram illustrating the operation of a conventional light reception amount stabilizing device.

FIG. 11 is an explanatory diagram for explaining a problem of the conventional device.

[Explanation of symbols]

 Reference Signs List 60 light reception amount stabilization device 61 glass substrate 63 rotation motor 65 mount 67a to 67l chrome deposition section

Continued on the front page. (72) Inventor Yoshikatsu Takeda 1-1-1, Wadazakicho, Hyogo-ku, Kobe City, Hyogo Prefecture Inside the Mitsubishi Heavy Industries, Ltd.Kobe Shipyard (72) Inventor Kunio Shibaike 2-1-1, Araimachi, Araimachi, Takasago-shi, Hyogo Prefecture No. 1 F term in Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (reference) 2F065 AA04 AA06 BB15 FF23 GG04 LL16 LL25 NN03 UU01 2H048 AA01 AA07 AA11 AA19 AA22 AA26

Claims (1)

[Claims] A plurality of separated chromium films formed by depositing a chrome film at intervals along the outer periphery of the glass substrate; A light receiving amount stabilizing device for a laser type position locating device, wherein an ND filter is formed, and the light transmittance of the plurality of ND filters through which the position locating laser light passes is changed stepwise.