JP3536892B2 - Laser distance 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 distance measuring device for measuring a distance to a target using a laser beam.
In particular, the present invention relates to a laser distance measurement device suitable for targeting a predetermined range such as the ground surface.

[0002]

2. Description of the Related Art A laser distance measuring device irradiates a laser beam toward a target, receives reflected light from the target, and measures a distance to the target based on a time difference between the irradiated light and the reflected light. Further, as a laser distance measuring device that targets a predetermined range of the ground surface, for example, there is a device mounted on a spacecraft that lands on a planet, and in this case, it is suitable for landing instead of simply measuring altitude. It is used to detect terrain.

[0003] As a laser distance measuring apparatus for a planetary explorer as described above, a laser at a predetermined altitude from the ground surface side is required.
In some cases, a laser beam is irradiated in the direction, and the distance to three points is measured to detect terrain such as a gradient in a range of a triangle connecting the three points.

[0004]

However, when a predetermined range on the ground surface is targeted, a laser distance measuring device that irradiates laser light in three directions as described above requires, for example, one of three points. In the case where the unevenness of the ground surface is severe, the error between the detection result in the range of the triangle and the actual terrain increases, it is difficult to improve the detection accuracy, and the emission of each laser beam in three directions Since a device and a light receiver are required, there is a problem that the size and weight of the device are increased, and it has been a problem to solve such a problem.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is a laser distance measuring apparatus suitable for targeting a predetermined range such as the ground surface, which improves detection accuracy. It is an object of the present invention to provide a small and lightweight laser distance measuring device that can be used.

[0006]

According to a first aspect of the present invention, there is provided a laser distance measuring apparatus, wherein a ring-shaped rotating body which rotates in a circumferential direction, and a laser beam is transmitted from above the rotating body onto a rotating shaft. Laser light transmitting means, and a light receiving sensor disposed above the rotating body and on the rotating shaft, and inside the rotating body, disposed on the rotating shaft and transmitting the laser light from the laser light transmitting means to the rotating shaft. A transmission mirror that reflects in a downward direction that is inclined with respect to, and a configuration that includes a condensing unit that receives laser light reflected by a target and reflects the laser light to a light receiving sensor,
As a second aspect, a ring-shaped rotating body is coaxially provided along the circumferential direction at the lower end of the cylindrical case opened to the lower side, and a light receiving sensor is provided at the center of the upper wall of the case. In addition, a laser light transmitting means for transmitting laser light on a rotation axis of the rotating body is arranged between the rotating body and the light receiving sensor, and the laser light transmitting means is arranged on the rotation axis inside the rotating body and is provided from the laser light transmitting means. 4. A converging device comprising: a transmitting mirror for reflecting a laser beam in a direction inclined with respect to a rotation axis; and a condensing unit for receiving the laser beam reflected on a target and reflecting the laser beam on a light receiving sensor. Is a converging mirror that forms a paraboloid. According to a fourth aspect, the converging means includes a converging lens and a converging mirror, and is reflected by the transmitting mirror at the center of the converging lens. It has a configuration with a through hole for passing laser light. And a means for solving the problems of the above configuration.

[0007]

In the laser distance measuring apparatus according to the first aspect of the present invention, laser light is transmitted from the laser light transmitting means on the upper side of the rotating body onto the rotating shaft of the rotating body, and this laser light is transmitted together with the rotating body. Scanning for rotating the laser light, that is, conical scan, is performed by making the laser light incident on the transmission mirror rotating inside and on the rotation axis and reflecting the laser light by the transmission mirror in a downward direction inclined with respect to the rotation axis. . Further, the laser beam reflected by the target is received by a condensing means rotating inside the rotating body together with the rotating body, and is input to a light receiving sensor arranged above the rotating body and on the rotating shaft. As described above, in the above laser distance measuring apparatus, since the laser light is continuously scanned in a circular shape, it is possible to measure the irregularities in the target in detail, and a simple structure using one laser light transmitting means and one light receiving sensor respectively. It becomes.

In the laser distance measuring apparatus according to the second aspect of the present invention, the case is provided with a laser beam transmitting means, a light receiving sensor and a rotating body, and the rotating body is provided with a transmitting mirror and a light collecting means. Thus, it is compact as a whole, and performs conical scanning in the same manner as in the first aspect.

In the laser distance measuring apparatus according to the third aspect of the present invention, since a converging mirror having a parabolic surface is used as the converging means, the laser light reflected by the target is transmitted to the light receiving sensor only by the converging mirror. The light can be focused toward it.

In the laser distance measuring apparatus according to a fourth aspect of the present invention, the laser light transmitted from the laser light transmitting means is reflected by a transmitting mirror and passed through a through hole of a condensing lens constituting the condensing means. The laser beam transmitted to the target side and reflected is converged in two stages by a converging lens and a converging mirror as a condensing means, and input to a light receiving sensor.

[0011]

According to the laser distance measuring apparatus according to the first aspect of the present invention, a laser distance measuring apparatus which targets a predetermined range such as the ground surface is continuously scanned by circular scanning (conical scanning) of the transmitted laser light. Measurement can be performed in detail, so that it is possible to measure the irregularities in the target in detail and to improve the detection accuracy. In addition, with a simple structure using one laser light transmitting means and one light receiving sensor, respectively. The above measurement can be performed, and the size and weight of the device can be reduced. In addition, the above laser distance measurement device has improved detection accuracy and reduced size and weight,
It is extremely suitable for use in planetary probes, and can be used for determining the attitude of the probe with respect to the surface of the planet, making accurate determinations possible and increasing the security of the entire system.

According to the laser distance measuring apparatus of the second aspect of the present invention, the same effect as that of the first aspect can be obtained, and most of the laser beam transmitting means, the light receiving sensor, and the rotating body are provided in the case. Since it is accommodated, the whole can be made compact, which can contribute to miniaturization and weight reduction.

According to the laser distance measuring apparatus of the third aspect of the present invention, the same effects as those of the first and second aspects can be obtained, and a converging mirror having a paraboloid is used as the converging means. By doing so, the structure of the light collecting means can be made extremely simple, and further reduction in size and weight can be realized.

According to the laser distance measuring apparatus of the fourth aspect of the present invention, the same effects as those of the first and second aspects can be obtained, and a condensing lens and a converging mirror are employed as the condensing means. As a result, the reflected laser light is condensed in two stages by the condensing lens and the condensing mirror, so that the size and weight of the condensing mirror can be particularly reduced, and for example, in the case as in claim 2, The accommodating property is improved. In addition, since the condenser lens is arranged on the rotation axis of the rotator with the downsizing of the condenser mirror, the center of gravity of the condensing means is closer to the rotation axis of the rotator, and a better rotation operation of the rotator is achieved. Can be realized.

[0015]

FIG. 1 is a view for explaining an embodiment of a laser distance measuring apparatus according to claims 1 to 3 of the present invention.

The laser distance measuring device L1 shown in FIG.
Is mounted on, for example, a planetary spacecraft, and includes a ring-shaped hollow motor 2 inside a lower end portion of a cylindrical case 1 opened to the lower side, and an upper wall portion 1 of the case 1.
A light receiving sensor 3 is mounted downward at the center of a in a coaxial arrangement with the rotation axis of the hollow motor 2, and a laser beam for transmitting laser light on the rotation axis of the hollow motor 2 is provided on a side wall 1 b of the case 1. Optical transmission means 4 is provided.

The hollow motor 2 is mounted coaxially with the case 1 and comprises an outer fixed body (stator) 5 fixed to the case 1 and an inner rotating body (rotor) 6. .

The laser beam transmitting means 4 is provided between the hollow motor 2 and the light receiving sensor 3, and is provided on the side wall 1b of the case 1.
And a reflecting mirror 9 attached to the distal end of the arm 8. The reflecting mirror 9 is attached to the rotating body 6 by the arm 8. It is held on a rotating shaft. The laser light transmitting means 4 reflects the laser light oscillated from the laser diode 7 downward by the reflection mirror 9 and transmits the laser light on the axis of the rotating body 6.

The rotating body 6 of the hollow motor 2 has a transmitting mirror 10 disposed on the rotating axis thereof and reflecting the laser light from the laser light transmitting means 4 in a direction inclined with respect to the rotating axis. A condensing mirror 11 is provided as condensing means for receiving the laser beam reflected by the target and reflecting the laser beam on the light receiving sensor 3.

As shown in FIG. 1B, the transmission mirror 10 is held on the rotation axis of the rotating body 6 by three stays 12 provided at intervals of 120 degrees. Is reflected obliquely downward. On the other hand, the condensing mirror 11 has a reflecting surface that is a paraboloid, and the transmitting mirror 1 is arranged in the traveling direction of the laser light reflected by the target.
0 and is fixed to the inner peripheral surface of the rotating body 6.

The laser distance measuring device L1 refers to a part of the laser light from the laser light transmitting means 4 in order to detect a time lag between the transmitted laser light and the received laser light, in addition to the above-described configuration. In addition to a means for inputting light to the light receiving sensor 3, a controller for performing signal processing for distance measurement and driving the hollow motor 2 and the laser light transmitting means 4 is provided. Further, a dome made of a material through which laser light can pass may be provided in the lower open portion of the case 1 to close the open portion.

Laser distance measuring device L having the above configuration
1 rotates the transmission mirror 10 and the condensing mirror 11 together with the rotating body 6 by driving the hollow motor 2, and as shown by a solid line arrow in FIG. The transmitting laser light LT is transmitted from the transmitting means 4 onto the rotation axis of the rotating body 6, and this transmitting laser light LT
Is incident on the transmission mirror 10 rotating inside and on the rotation axis together with the rotating body 6, and the transmission laser light LT is reflected by the transmission mirror 10 in a downward direction inclined with respect to the rotation axis, so that transmission is performed. A scan for rotating the laser beam LT, that is, a conical scan is performed.

As shown by a dotted arrow in the drawing, the receiving laser beam LR reflected by a target (not shown) is received by the condensing mirror 11 rotating inside the rotating body 6 together with the rotating body 6, and And input to the light receiving sensor 3 arranged on the rotation axis.

As described above, the laser distance measuring device L1
In the case 1, most of the laser light transmitting means 4, the light receiving sensor 3 and the rotating body 6 are accommodated in the case 1, and the whole is compact and one laser light transmitting means 4 and one light receiving sensor 3 are used. It has a simple structure, and by continuously scanning the transmission laser beam LT in a circular shape, it is possible to measure the irregularities in the target in detail. Further, since the condensing mirror 11 having a paraboloid is used as the condensing means, the received laser light LR reflected on the target is reliably reflected on the rotation axis of the rotating body 6 only by the condensing mirror 11.
Input can be made to the light receiving sensor 3 located on the rotation axis.

FIG. 2 is a view for explaining an embodiment of a laser distance measuring apparatus according to claims 1, 2 and 4 of the present invention. The same components as those in the previous embodiment are denoted by the same reference numerals, and detailed description is omitted.

The illustrated laser distance measuring device L2 includes a condensing lens 15 and a condensing mirror 16 as condensing means inside the rotating body 6. The condenser lens 15 is formed by a plurality of stays 12 provided on the rotating body 6, and the transmission mirror 1 is provided.
The transmission laser beam LT reflected by the transmission mirror 10 is held on the rotation axis of the rotating body 6 together with the transmission mirror 10 in the transmission direction of the transmission laser beam LT by the transmission mirror 10. A through hole 17 is provided to allow the passage.
The condenser mirror 16 is attached to the inner peripheral surface of the rotating body 6,
The reception laser light LR condensed by the condenser lens 15 is further converged toward the light receiving sensor 3.

In the above-described laser distance measuring device L2, the transmitting mirror 10, the converging lens 15, and the converging mirror 16 are rotated together with the rotating body 6, and the transmitting laser light LT transmitted from the laser light transmitting means 4 is transmitted. The laser beam is reflected by the trust mirror 10 and transmitted to the target side through the through hole 17 of the condenser lens 15, and the transmission laser beam LT is rotationally scanned with the rotation of the rotating body 6, and the reflected reception laser beam LR is reflected. The light is condensed in two stages by the condenser lens 15 and the condenser mirror 16 and input to the light receiving sensor 3.

In such a laser distance measuring device L2,
Since the condenser lens 15 and the condenser mirror 16 are employed as the condenser means, the condenser mirror 1 is compared with the first embodiment.
6 is small in size and light in weight, has good housingability in the case 1, and furthermore, with the downsizing of the condenser mirror 16, the condenser lens 15 is arranged on the rotation axis of the rotating body 6. Therefore, the center of gravity of the light condensing means is closer to the rotation axis of the rotating body 6, which can contribute to prevention of vibration of the rotating body 6.

In each of the above embodiments, the laser beam transmitting means 4 includes the laser diode 7, the arm 8, and the reflection mirror 9. However, the stay 7 is used to connect the laser diode 7 to the rotating shaft of the rotating body 6. The transmission laser light from the laser diode 7 is held on the transmission mirror 10.
May be directly transmitted to the server.

Further, as compared with the state shown in each figure, the light collecting means (1
1, 15, 16) is arranged below the rotating body 6, the area of the received laser light passing through the inside opening of the rotating body 6 becomes small, and the condensing mirror (11, 16) is formed.
16) Because of the bias toward the side, for example, it is possible to provide a cover that partially closes the inside of the rotating body 6 for the purpose of protecting the internal structure, or it is possible to reduce the size of the hollow motor 2. is there.

[Brief description of the drawings]

FIG. 1 is a sectional view (a) for explaining an embodiment of a laser distance measuring apparatus according to claims 1 to 3 of the present invention, and a plan view (b) of a rotating body.

FIG. 2 is a sectional view illustrating an embodiment of a laser distance measuring device according to claims 1, 2 and 4 of the present invention.

[Explanation of symbols]

L1 L2 Laser distance measuring device 1 case 3 Light receiving sensor 4 Laser light transmission means 6 rotating body 10 Mirror for transmission 11 Condensing mirror (condensing means) 15 Condensing lens (condensing means) 16 Condensing mirror (condensing means) 17 Through hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 G01C 3/00-3/32 G01S 17/00-17/88

Claims (4)

(57) [Claims] 1. A ring-shaped rotating body that rotates in a circumferential direction, a laser beam transmitting unit that transmits laser light from above the rotating body to a rotating shaft, and is disposed above the rotating body and on the rotating shaft. A transmitting mirror disposed on the rotation axis inside the rotating body and reflecting the laser light from the laser light transmitting means in a downward direction inclined with respect to the rotation axis; A laser distance measuring device, comprising: a focusing unit that receives the reflected laser beam and reflects the reflected laser beam to a light receiving sensor. 2. A ring-shaped rotator is provided coaxially along the circumferential direction at the lower end of a cylindrical case opened to the lower side, and a light receiving sensor is provided at the center of the upper wall of the case. In addition, a laser light transmitting means for transmitting laser light on a rotation axis of the rotating body is arranged between the rotating body and the light receiving sensor, and the laser light transmitting means is arranged on the rotation axis inside the rotating body and is provided from the laser light transmitting means. A laser distance measuring device comprising: a transmission mirror that reflects laser light in a direction inclined with respect to a rotation axis; and a light condensing unit that receives laser light reflected by a target and reflects the laser light to a light receiving sensor. 3. The laser distance measuring apparatus according to claim 1, wherein the light condensing means is a converging mirror forming a paraboloid. 4. The light-collecting means includes a light-collecting lens and a light-collecting mirror, and a through-hole is provided at the center of the light-collecting lens for passing the laser beam reflected by the transmission mirror. The laser distance measuring device according to claim 1.