JP3408767B2 - Laser angle measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser angle measuring device used for guidance and position measurement in an autonomous vehicle, a moving device, etc., and for measuring and abnormalities of natural objects and large structures.

[0002]

2. Description of the Related Art A laser beam is projected from a vehicle onto a retroreflector, which is a landmark installed at a plurality of places in a field, and the reflected light is received to measure the position of the vehicle (angle and coordinates of the vehicle). There is a measuring device that does. In the laser light projecting / receiving device of this measuring device, a reflecting mirror for separating the projected laser light and the reflected laser light is installed in order to set the light projecting position and the light receiving position at the same position. This conventional reflection mirror is configured by a perforated mirror type in which a through hole for passing the projection laser light is formed at the center position, or the whole reflection mirror is formed by a half mirror type. It was

The retroreflector referred to here is not limited to one that reflects all the incident light in parallel with the incident light, but is intentionally installed to reflect the light from the angle measuring device to the angle measuring device. Point to the reflector. There is a corner cube in the reflector that reflects all the incident light in parallel with the incident light. As a part of the reflector, a cylindrical semi-body, a bead (sphere) semi-body, or a bead-shaped semi-body There is something embedded.

[0004]

However, when the vehicle has a wide range of motion, it is necessary to accurately detect the weak reflected laser light from the retroreflector. The half mirror type with reflection loss has a problem that the reflected laser light is attenuated and the light collecting ability is low.

The present invention solves the above problems and provides a laser angle measuring device capable of more effectively converging a retroreflected laser beam, accurately detecting a weak reflected laser beam, and accurately detecting a position. The purpose is to

[0006]

In order to achieve the above object, the present invention provides a reflection mirror which is arranged on the projection optical axis of a projection laser beam projected from a laser oscillator at a predetermined angle, and the reflection mirror. To the retro-reflector, a total reflection rotary mirror that is tilted at a predetermined angle with respect to the projection optical axis from and is rotatably arranged around the projection optical axis, a rotary encoder that detects the rotation angle of the total reflection rotary mirror, The angle of the retroreflector is determined by the light receiving element arranged on the reflection optical axis where the retroreflected laser light reflected and returned is reflected by the reflection mirror through the total reflection rotating mirror, and the signal from the light receiving element and the rotary encoder. An angle measuring section for detecting a position is provided, and a half mirror section having a high transmittance is provided in the central portion of the reflection mirror, and a total reflection mirror having a low transmittance is provided on an outer peripheral portion thereof. It is obtained by forming a chromatography unit.

According to the above construction, the output of the projected laser light to the outside of the device is limited by the regulation, but the output of the laser light inside the device is not limited. Therefore, by increasing the output of the laser oscillator, A constant output can be secured for the laser light to the outside. Therefore, as compared with the conventional perforated mirror type, the recursive laser beam condensed by the light receiving element can be condensed more because the through-hole is reflected by the half mirror. Compared with, the loss at the time of reflection is small, so the light collection ability is high, and even the weak reflected laser light reflected by the retroreflector at a long distance can be detected with high accuracy, and it can be detected at a long distance. The angle with respect to a certain retroreflector can be measured with high accuracy. Moreover, when this laser angle measuring device is mounted on a moving body, the number of retroreflectors in a certain range of field can be reduced.

According to a second aspect of the present invention, a half mirror for reflecting the projection laser light projected from the laser oscillator along the projection optical axis onto the reflection projection optical axis, and the reflection projection optical axis of the half mirror. A total reflection rotary mirror that is tilted at a predetermined angle with respect to and is rotatably arranged around a reflection projection optical axis and projects the projected laser light onto a retroreflector; and a rotary encoder that detects the rotation angle of the total reflection rotary mirror. And the retro-reflecting laser light reflected back to the retro-reflector is incident from the total reflection rotating mirror along the reflection projection optical axis and passes through the half-mirror and its periphery and is received on the reflection projection optical axis. The light receiving element and an angle measuring unit for detecting the angular position of the retroreflector based on signals from the light receiving element and the rotary encoder are provided. Of the, and is formed to correspond to the optical diameter of the projected laser beam.

According to the above structure, the output of the projected laser light to the outside of the device is limited by the regulation, but the output of the laser light inside the device is not limited. Therefore, the output of the laser oscillator is increased. A constant output can be secured for the laser light to the outside. Therefore, the retroreflected laser beam focused on the light receiving element can be focused more as much as it passes through the half mirror than the conventional perforated mirror type, and compared with the conventional half mirror type. Since the transmission loss is small, the light collection ability is high, and even the weak reflected laser light reflected by the retroreflector at a long distance can be detected with high accuracy, and the angle to the retroreflector at a long distance can be detected. Can be measured with high accuracy. Moreover, when this laser angle measuring device is mounted on a moving body, the number of retroreflectors in a certain range of field can be reduced.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Here, an embodiment of a laser angle measuring apparatus according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, this angle measuring device projects laser light over the entire circumference from a moving body 1 which automatically travels along a predetermined path of a field, and is installed as a landmark at a plurality of places of the field. By detecting the retro-reflected laser light reflected by the reflected retro-reflector R, the angle of the retro-reflector R seen from the reference (for example, the traveling direction) of the moving body 1 is measured to determine the position of the moving body 1. It is for detection.

That is, a retroreflector installed as a landmark by projecting a projection laser beam (beam) from a laser light projecting / receiving device 2 arranged on a moving body 1 through a total reflection rotary mirror 3 in all angular directions. The light is reflected by R in the same direction, and the retroreflected laser light is detected by the light projecting / receiving device 2 via the rotating mirror 3. Then, the retro laser light is detected from at least three retroreflectors R whose installation positions are known,
The position of this angle measuring device is detected from the difference between the detection angles of the three recursive laser beams detected continuously, and as a result, the position and traveling direction of the moving body 1 equipped with the angle measuring device are detected.

That is, the laser light projecting / receiving device 2 installed in the housing 1a has a laser oscillator 4 for projecting the laser light Ls upward and a projection optical axis Os of the projected laser light Ls, for example, 45. On the reflecting mirror 5 which is arranged with a tilt angle and allows the projected laser light from the laser oscillator 4 to pass therethrough, and which reflects the recursive laser light Lr, and the reflecting optical axis Or of the recursive laser light Lr reflected by the reflecting mirror 5. Condensing lens 6 and light receiving element 7 arranged
It has and. Then, the reflection mirror 5 transmits the projection laser light Ls at the central half mirror portion 5a, and reflects the retroreflected laser light Lr in the direction of the reflection optical axis Or by the half mirror portion 5a and the total reflection mirror portion 5b around it. Configured to let.

The housing 1a is provided with a rolling bearing 12 rotatable on the projection optical axis Os about the projection optical axis Os, and the projection optical axis Os is provided at the outer end of the rotating portion 11 of the rolling bearing 12. A total-reflection rotary mirror 3 tilted at 45 degrees with respect to is attached. Further, a passive timing gear 13 is formed on the rotating portion 11, and the passive timing gear 13 is formed.
A timing belt 16 is wound around and interlocked with a drive timing gear 15 which is rotationally driven by the rotary motor 14. Further, the rotary conduit 11 is provided with a rotary encoder 17 for detecting a rotation angle.

The detection signal of the light receiving element 7 is input to the processing unit 9 which is an angle measuring unit via the amplifier 8, and the rotation angle signal from the rotary encoder 17 is input to the counter unit of the processing unit 9 for processing. In the device 9, the output of the counter unit when the light receiving element 7 is detected is calculated as the detection angle of the retroreflector R.

As an example of the reflection mirror 5, as shown in FIG. 2, a through hole 21a having a diameter of 8 to 10 mm is formed at the center.
The total reflection mirror portion 5 is formed by the perforated mirror 21 in which the
b is formed, and the half mirror portion 5a is formed by the half mirror plate 22 attached to the through hole 21a.

As another example of the reflection mirror 5, as shown in FIGS. 3 and 4, a non-metallic mirror surface material 32 is formed on the entire surface of one glass base material 31 with a predetermined film thickness or a metal mirror surface material. 33 is vapor-deposited at a predetermined density to obtain a transmittance T. R. 50%
A half mirror of (T: R = 5: 5) is formed, and the half mirror portion 5a corresponding position of this half mirror is masked, and the same or different non-metallic mirror surface material 32 or metal mirror surface material 33 is vapor-deposited. , Total reflection mirror section 5b for total reflection
To form. Accordingly, the half mirror portion 5b having a diameter of 8 to 10 mm and the total reflection mirror portion 5b around the half mirror portion 5b can be integrally formed on the surface of one glass base material 31.

As still another example, one glass base material 3
The corresponding portion of the total reflection mirror portion 5b of No. 1 is masked, and the non-metal specular material 32 is given a predetermined thickness or the metal specular material 33
Is vapor-deposited at a predetermined density and the transmittance T. R. 50% (T: R
= 5: 5) half mirror portion 5a is formed, and the half mirror portion 5a is masked to vapor-deposit the same or different non-metallic mirror surface material 32 or metal mirror surface material 33 to form a total reflection mirror portion 5b for total reflection. Form integrally. The half mirror portion 5a may be formed after the total reflection mirror portion 5b is formed by the reverse procedure.

The half mirror portion 5a is formed on the glass base material 3
It is also possible to form the total reflection mirror portion 5a on the back surface of No. 1 and on the front surface, respectively.

Here, the non-metallic mirror surface material 32 forming the half mirror portion 5a and the total reflection mirror portion 5b is Zn.
S, CeO ₂ , TiO ₂ or the like is used, and Al, Ag, Cr, Au or the like is used for the metal mirror surface material 33. Further, when the non-metallic mirror surface material 32 is used, a material having a high reflectance at the wavelength of the laser light used for the reflection mirror 5 and a low reflectance at other wavelengths or an adhesion method is selected, that is, the refractive index of the material. The reflectance with respect to wavelength is determined by the film thickness and the film thickness. By selecting a material according to this refractive index and forming a mirror surface, it is possible to exert a filter function that can eliminate other extra light (noise). it can.

According to the above embodiment, the output of the laser light emitted indoors and outdoors is restricted by regulation, and there is no restriction on the output inside the device. Therefore, the laser oscillator 4
By increasing the output of, the output of the projection laser light Ls that has passed through the half mirror portion 5a can ensure the output of the limit value. Therefore, as compared with the conventional perforated mirror type, the recursive laser beam Lr can collect a large amount of the recursive laser beam Lr 'whose reflection portion is reflected by the half mirror portion 5a. Further, as compared with the conventional half mirror type, the light collecting ability can be increased by the loss at the time of reflection. Therefore, even the weak retroreflected laser light Lr reflected by the long-distance target reflector 1a can be recognized with high accuracy. Therefore, in this laser angle measuring device, even if the traveling range of the moving body 1 is widened, the retroreflector R
It is possible to detect the feeble retro-laser light Lr from the object with high accuracy and to detect the coordinate angle of the moving body 1 with respect to the retro-reflector R more accurately. Therefore, it is possible to reduce the number of retroreflectors R to be installed in a field having a certain size, and it is also possible to reduce the facility cost.

FIG. 5 shows another embodiment of the angle measuring device.
This embodiment is the laser oscillator 4 of the previous embodiment.
And the positions of the condenser lens 6 and the light receiver 7 are interchanged, the same members are designated by the same reference numerals, and description thereof will be omitted.

That is, the projected laser light Ls projected from the laser oscillator 4 is reflected by the half mirror 41 on the projection optical axis Os1 and projected on the total reflection rotary mirror 3 along the reflection projection optical axis Os2. This half mirror 41
Is arranged on the projection optical axis Os1 at an angle of, for example, 45 °, and it is desirable that the diameter be approximately the same as the diameter of the projection laser light Ls. The reason is that when the half mirror 41 is smaller than the light diameter, the light amount is reduced at the stage of light projection, and conversely, when it is larger than the light diameter, the loss of the received light amount is large. Is. However, the half mirror 41
The size of is determined by the balance with the measurement range and the output of laser light.

The retroreflected laser beam Lr reflected back to the retroreflector R is reflected by the total reflection rotary mirror 3 and goes straight along the reflection projection optical axis Os2, and is condensed through the half mirror 41 and its periphery. It is configured to be detected by the light receiving element 7 from the lens 6.

According to this embodiment, as compared with the conventional perforated mirror or the like, the retro-reflecting laser beam Lr can be detected by the light-receiving element 7 as much as it passes through the half mirror 41, and the retro-reflector can be detected. Weak recursive laser beam Lr from R
Can be detected with high accuracy, and the coordinate angle of the moving body 1 with respect to the retroreflector R can be detected more accurately, and the same effect as that of the previous embodiment can be obtained.

[0026]

As described above, according to the present invention, the output of the projected laser light to the outside of the device is limited by the regulation, but the output of the laser light inside the device is not limited. By increasing the output of the laser light, a constant output can be secured for the laser light outside the device. Therefore, as compared with the conventional perforated mirror type, the recursive laser beam condensed by the light receiving element can be condensed more because the through-hole is reflected by the half mirror. Compared with, the loss at the time of reflection is small, so the light collection ability is high, and even the weak reflected laser light reflected by the retroreflector at a long distance can be detected with high accuracy, and it can be detected at a long distance. The angle with respect to a certain retroreflector can be measured with high accuracy. Moreover, when this laser angle measuring device is mounted on a moving body, the number of retroreflectors in a certain range of field can be reduced.

According to the second aspect of the invention, the output of the projected laser beam to the outside of the apparatus is limited by the regulation,
Since the output of the laser light inside the device is not limited, a constant output of the laser light outside the device can be secured by increasing the output of the laser oscillator. Therefore,
Compared to the conventional perforated mirror type, the recursive laser light that is focused on the light receiving element can be condensed more because it passes through the half mirror, and also has a transmission loss compared to the conventional half mirror type. As the amount of light is small, even the weak reflected laser light reflected by the retroreflector at a long distance can be detected with high accuracy because of its high light collecting ability, and the angle to the retroreflector at a long distance can be increased. It can be measured with accuracy. Moreover, when this laser angle measuring device is mounted on a moving body, the number of retroreflectors in a certain range of field can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a laser angle measuring device according to the present invention.

FIG. 2 is a sectional view of the reflection mirror.

FIG. 3 is a perspective view showing another embodiment of the reflection mirror.

FIG. 4 is a cross-sectional view showing another embodiment of the reflection mirror.

FIG. 5 is a configuration diagram showing another embodiment of the laser angle measuring device according to the present invention.

[Explanation of symbols]

1 moving body 2 Laser light projector / receiver 3 rotating mirror 4 laser oscillator 5 reflection mirror 5a Half mirror part 5b Total reflection mirror section 7 Light receiving element 9 counter 14 Rotary drive motor 17 Rotary encoder 21 perforated mirror 21a through hole 22 Half mirror plate 31 glass base material 32 Non-metallic materials 33 metal materials 41 Half mirror R retroreflector Ls projection laser light Lr Recursive laser light Os Projection mirror optical axis Or reflective mirror optical axis

Front page continuation (72) Inventor Hirotoshi Shimoda 1-7 89 Minami Kohoku, Suminoe-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. No. Toyo Transporter Co., Ltd. (72) Inventor Hisatoshi Narasaki 1-15-10 Kyomachibori, Nishi-ku, Osaka City, Osaka Prefecture Toyo Transporter Co., Ltd. (56) Reference JP-A-1-254806 (JP, A) Kaihei 7-134026 (JP, A) JP 7-318648 (JP, A) JP 63-317706 (JP, A) JP 2000-249816 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) G01C 1/00 G01C 15/00

Claims (2)

(57) [Claims] 1. A reflection mirror, which is arranged on the projection optical axis of a projection laser beam projected from a laser oscillator, at a predetermined angle, and at the same time is tilted at a predetermined angle with respect to the projection optical axis from the reflection mirror. A total reflection rotary mirror that is rotatably arranged around the optical axis, a rotary encoder that detects the rotation angle of the total reflection rotary mirror, and a retroreflected laser beam that is reflected back to the retroreflector through the total reflection rotary mirror. A light receiving element disposed on the reflection optical axis reflected by the reflection mirror; and an angle measuring unit for detecting an angular position of the retroreflector based on a signal from the light receiving element and the rotary encoder. The laser measurement is characterized in that the mirror is provided with a half-mirror portion having high transmittance in the central portion and a total reflection mirror portion having low transmittance is formed on the outer peripheral portion thereof. Apparatus. 2. A half mirror for reflecting projection laser light projected from a laser oscillator along a projection optical axis onto a reflection projection optical axis, and being inclined at a predetermined angle with respect to the reflection projection optical axis of the half mirror. A total reflection rotary mirror that is rotatably arranged around a reflection projection optical axis and projects the projected laser light onto a retroreflector; a rotary encoder that detects a rotation angle of the total reflection rotary mirror; A light receiving element disposed on the reflection projection optical axis where the recursive laser light is returned from the total reflection rotating mirror along the reflection projection optical axis and is received by passing through the half mirror and its periphery, and the light receiving element and the above-mentioned light receiving element. And an angle measuring unit for detecting the angular position of the retroreflector according to a signal from the rotary encoder, wherein the size of the half mirror is the optical diameter of the projected laser beam. Laser angle measuring apparatus being characterized in that formed correspondingly.