JPH11166832A - Laser surveying system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser surveying system which consumes less power to extend the life of a laser diode. SOLUTION: This laser surveying system has a beam emission means 11 for emitting a laser beam, a rotary scanning means 12 for projecting and scanning the laser beam toward a target 21 installed on a subject for measurement, a beam reception means 13 for receiving the laser beam reflected by the target 21, and a control means 15 for obtaining information about the position of the target 21 from the laser beam received. In this case, the control means 15 causes the beam emission means 11 to emit the beam when the beam is scanned within a predetermined range of angles including the direction of the target 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser surveying system for measuring the displacement of a structure, particularly the settlement of a large structure.

[0002]

2. Description of the Related Art In a conventional laser surveying system, a laser projector forming a horizontal plane is projected and scanned by a laser projector installed at a fixed point near an object to be measured, and reflected by a target attached to the object to be measured. The laser beam was received, and positional information such as displacement from a horizontal plane formed by the laser beam was measured.

FIG. 6 is a configuration diagram of a conventional laser surveying system. The main body 1 is installed at a fixed point such as on a solid ground, and emits the laser beam LA to targets 21 (1) to (4) attached to the structure 2 to be measured. The projected laser beam LA is rotationally scanned over 360 degrees in the direction of arrow 3 to form a horizontal plane serving as a reference for measurement. A reflection plate is provided on each of the targets 21 (1) to (4), and reflects the projected laser beam LA as a laser beam LB in the projected direction.

The reflectors of the targets 21 (1) to (4) have, for example, a triangular shape.
If (4) is displaced in the vertical direction with respect to the horizontal scanning direction, the pulse width of the laser beam LB reflected by the reflector changes. The laser beam LB reflected by the targets 21 (1) to (4) is received by the main body 1. The main unit 1 measures the pulse width of the laser beam LB reflected by each of the targets 21 (1) to (4), and
The displacement information of (1) to (4) is obtained.

On the other hand, a laser surveying system is used for measuring settlement of a large structure such as a bridge girder or a bridge on a highway, and the measurement place is often outdoors. Further, the main body 1 for projecting and scanning the laser beam must be installed at a solid fixed point on the ground, and a commercial power supply may not be obtained in some cases. For this reason, the laser surveying system is often driven by a battery.

[0006]

However, the conventional laser surveying system emits laser light continuously and rotates and scans the laser light in a direction of 360 degrees to form a reference horizontal plane. Therefore, a large amount of power is consumed by emitting a laser beam in a direction other than the direction of the target necessary for measurement.

Further, in the conventional laser surveying system, the amount of laser light emitted by a laser diode or the like is set to be large in order to widen the measurable range. Without
A large amount of laser light was emitted. For this reason, when the object to be measured is at a short distance, the amount of reflected laser light exceeds the amount of light necessary for measurement, and the laser diode of the light emitting unit consumes useless power.

[0008] In addition, the laser surveying system is often used continuously over a long period of time to measure the subsidence of a large structure, for example, several mm per year. For this reason, the laser surveying system is used continuously for a long period of time, but the laser diode that emits laser light has a short emission life due to long-term continuous light emission.

Further, when the light amount of the laser light emitted by the laser diode or the like is set to a predetermined value at the start of the measurement, the measurement has been continued as it is. For this reason,
If the target reflector is contaminated by use for a long period of time, the amount of reflected laser light may become less than the amount required for measurement, making measurement impossible.

It is an object of the present invention to provide a laser surveying system with low power consumption and a long laser diode life.

[0011]

The object of the present invention is to provide a light emitting means for emitting laser light, a rotary scanning means for projecting and scanning the laser light toward a target placed on an object to be measured, and the target In a laser surveying system having a light receiving means for receiving the laser light reflected by the laser light and a control means for acquiring the position information of the target from the received laser light, the control means comprises a predetermined angle including a direction of the target. This is attained by providing a laser surveying system, wherein the light emitting means emits light when scanning within a range.

According to the present invention, laser light is emitted only in the direction in which the target required for measurement exists, so that the power consumption of the light emitting means is reduced as compared with the conventional case where laser light is emitted in all directions at 360 degrees. In addition to the reduction, the light emitting life of the light emitting means can be extended.

Further, the control means of the present invention is arranged such that the rotary scanning means rotates the laser light in a 360-degree direction in advance, and the light scanning means detects the laser light from the scanning direction when the light receiving means receives the laser light. , Detecting a direction of the target.

According to the present invention, a laser surveying system comprises:
Prior to the measurement, the direction of the target is detected by rotating and scanning the laser light in a 360-degree direction, and then the measurement is shifted to the projection of the laser light only in the direction of the target. There is no need to input, and measurement can be performed quickly.

[0015] Further, the above object is to provide a light emitting means for emitting laser light, a rotary scanning means for projecting and scanning the laser light toward a target placed on an object to be measured, and a laser reflected by the target. In a laser surveying system having light receiving means for receiving light and control means for acquiring position information of the target from the received laser light, the control means detects an amount of laser light received by the light receiving means The present invention is also achieved by providing a laser surveying system characterized by changing the amount of laser light emitted by the light emitting means according to the amount of received light.

According to the present invention, even if the reflector of the target becomes dirty due to long-term use and the amount of laser light reflected by the reflector decreases, the control means increases the amount of light emitted from the light emitting means, Measurement can be prevented from becoming impossible.

Further, according to the present invention, when the target is at a short distance, the light emission amount of the laser light emitted by the light emitting means is reduced to a range necessary for measurement, so that the light emitting means is uniformly large in light amount. In this case, the power consumption of the light emitting means can be reduced and the light emitting life of the light emitting means can be extended as compared with the case where the light emitting means is used.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, such embodiments do not limit the technical scope of the present invention.

FIG. 1 shows a configuration diagram (1) of a laser surveying system according to an embodiment of the present invention. The main body unit 1 is installed at a fixed point and emits the laser beam LA to the target 21 (1), (2), (3), attached to the structure 2 to be measured.
Light projection scanning is performed in (4). In the main body 1, there is a rotating unit composed of a prism and a pentamirror, which will be described later.
Rotated over 0 degrees.

However, in the present embodiment, a laser diode, which will be described later, is not continuously emitted so that the laser beam LA is scanned 360 degrees in all directions, and the targets 21 (1) and (2) detected or set in advance are not emitted. ), (3) and (4) are emitted only in the range of the angle 4 including the directions. The laser beam LA emitted from the laser diode is rotationally scanned by a rotating unit to form a horizontal plane that is a reference for measurement. Therefore, in this embodiment, since the laser diode emits light only in the range of the angle 4 required for measurement, power consumption can be reduced and the emission life of the laser diode can be extended.

Each of the targets 21 (1) to (4) is provided with a reflecting plate in which a small corner cube or a spherical reflector is formed in a sheet shape. Reflected as LB.

The reflectors of the targets 21 (1) to (4) have a shape in which two right triangles are arranged in opposite directions, for example, as described in Japanese Patent Application Laid-Open No. 7-198382 by the present applicant. The pulse width of the laser beam LB reflected at each part is the target 21 (1) to 21 (1).
It changes due to the vertical displacement of (4). Target 2
The laser beam LB reflected by 1 (1) to (4) is
Is received at. The main body 1 includes the respective targets 21
The pulse width of the laser beam LB reflected in (1) to (4) is measured, and position information such as vertical displacement of each target 21 is acquired.

FIG. 2 shows a configuration diagram (2) of the laser surveying system according to the embodiment of the present invention. In the present embodiment, the laser diode is a target 2 previously detected or set.
Light is emitted only in the range of angles 4 (1), (2), (3), and (4) including the directions of 1 (1), (2), (3), and (4), respectively. In the present embodiment, the laser diode emits light intermittently only at an angle within the minimum range required for measurement, so that power consumption can be further reduced and the emission life of the laser diode can be further extended.

FIG. 3 shows an optical device of the main body 1 of the present embodiment. The laser diode 11 emits a laser beam according to a light emission command signal from a control unit described later. The laser light emitted from the laser diode 11 is made substantially collimated by the collimator lens 30 and enters the half prism 31. The light that has entered the half prism 31 travels straight as it is, is reflected by pentamirrors 33 and 34, and is emitted as laser light LA toward the target 21.

The laser beam LB reflected by the target 21
Are reflected by the pentamirrors 34 and 33 and enter the half prism 31. The light incident on the half prism 31 is
The path is changed in the right angle direction, and the light enters the condenser lens 32. The light incident on the condenser lens 32 is converged on the photodiode 13 and photoelectrically converted. The signal photoelectrically converted by the photodiode 13 is sent to a control unit described later, and the control unit acquires the position information of the measurement target included in the laser beam LB reflected by the target 21.

The amount of light received by the photodiode 13 is
It is detected by a light receiving amount detecting means described later and sent to the control means as a light receiving amount signal. When the received light amount is equal to or more than a predetermined reference received light amount that is not affected by noise or the like, the control unit reduces the driving voltage of the laser diode 11 so that the received light amount of the photodiode 13 becomes the reference received light amount.
The light emission amount of the laser diode 11 is reduced. As a result, the power consumption of the laser diode 11 is reduced, and the emission life of the laser diode can be extended.

The rotating unit 12 (3)
(1) is rotated via the belt 12 (2). A pentamirror 33 fixed to the rotating unit 12 (3),
34 rotates with the rotation unit 12 (3). The laser light LA emitted from the laser diode 11 is reflected by the pentamirrors 33 and 34, is projected to the outside, and is rotationally scanned to form a horizontal plane serving as a reference for measurement.

The encoder disk 14 (1) is fixed to the rotating unit 12 (3) and rotates together with the rotating unit 12 (3). The rotation angle of the encoder disk 14 (1) is
Detected by the detector 14 (2) fixed to the main body,
An angle signal is sent to the control means. In the control means, the photodiode 13 detects the reflected laser light L from the target 21.
By receiving the angle signal of the detector 14 (2) when receiving B,
The direction in which the target 21 exists can be detected.

FIG. 4 is a block diagram (1) of a laser surveying system according to an embodiment of the present invention. The light emitting means 11 in the main body 1 is composed of a laser diode or the like, and emits a laser beam L to the rotary scanning means 12 according to a light emission command signal S1 from the control means 15. The rotary scanning means 12 is composed of a rotary unit incorporating a prism or the like and a motor as described above, and the rotary unit is continuously rotated in a 360-degree direction by the motor.

The laser beam L emitted from the light emitting means 11 is horizontally scanned by the rotary scanning means 12 in a horizontal direction.
The light is projected on the target 21 as A. Rotary scanning means 1
2 is provided with an encoder 14, and the encoder 14 is provided with a rotation angle of the rotary scanning unit 12, that is, a laser beam L.
The projection direction of A is detected with high accuracy, and an angle signal S3 is output to the control unit 15.

The target 21 is set on an object to be measured,
The projected laser beam LA is reflected as a laser beam LB in the projected direction. As described above, for example, vertical position information of the target 21 is added to the laser beam LB.

Laser light LB reflected by target LB
Is received by the light receiving means 13 such as a photodiode.
The light receiving means 13 photoelectrically converts the received laser light LB,
The reception signal S4 corresponding to the pulse width of the laser light LB is output to the control unit 15.

The control means 15 is constituted by a microcomputer or the like, and acquires the position information of the target 21 included in the pulse width of the reception signal S4 from the light receiving means 13.
At the start of the measurement, the control means 15 causes the light emitting means 11 to emit light continuously by the light emission command signal S1, and the laser light LA
Is rotated and scanned in a direction of 360 degrees. Then, from the angle signal S3 when the light receiving means 13 receives the laser beam LB,
The direction in which the laser beam LB is reflected, that is, the target 2
1 direction is detected.

After detecting the direction of the target 21, the control means 15 outputs the light emission command signal S1 only when the rotary scanning means 12 scans the direction in which the target 21 is present and the angular range obtained by adding a margin before and after the direction. Output and laser light L
To emit light intermittently. For this reason, the light emitting unit 11 emits light intermittently only when scanning in a direction required for measurement, thereby reducing power consumption and extending the life of the light emitting element of the light emitting unit 11.

However, if the direction in which the target 21 exists is known in advance, the information can be given to the control unit 15 so that the laser beam can be emitted only when scanning in that direction. For example, there is a case where the target 21 exists only in the range of 180 degrees on the east side.

FIG. 5 is a block diagram (2) of a laser surveying system according to another embodiment of the present invention. The description of the parts common to FIG. 4 is omitted, and different parts will be described.

When the light receiving means 13 in the main body 1 receives the laser beam LB reflected by the target 21, it outputs a light receiving signal S5 proportional to the received light amount to the received light amount detecting means 16. The received light amount detecting means 16 outputs a received light amount signal S6 representing the received light amount of the laser beam LB received by the light receiving means 13 to the control means 1.
5 is output.

The control means 15 compares the received light amount signal S6 with a reference value indicating a reference received light amount required for measurement, and when the received light amount signal S6 is larger than the reference value, indicates the drive voltage of the laser diode. The light emission amount control signal S2 is output to the light emitting means 11, and the light emission amount of the light emitting means 11 is reduced so that the light reception amount of the light receiving means 13 becomes the reference light reception amount. Thus, when the target 21 is at a short distance and the amount of the received laser light LB is large, the light emission amount of the laser diode is reduced, the power consumption is reduced, and the light emission life of the laser diode is extended. it can.

If the reflector of the target 21 becomes dirty due to use for a long period of time, the laser beam L reflected by the reflector is reflected.
The light amount of B decreases, and the light receiving amount of the light receiving unit 13 decreases.
The received light amount signal S of the received light amount detecting means 16
6 is less than the reference value, priority is given to avoiding measurement failure, and the control means 15
It is also possible to increase the light emission amount of the light emitting means 11 so that 6 becomes the reference value.

[0040]

As described above, according to the present invention, the light emitting means emits light intermittently only in the direction necessary for measurement, so that the power consumption of the laser surveying system can be reduced.

When the laser surveying system is driven by a battery, the continuous operation time can be extended by lowering the power consumption.

Further, by intermittently driving the laser diode or the like, the life of the laser diode can be extended.

[Brief description of the drawings]

FIG. 1 is a configuration diagram (1) of a laser surveying system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram (2) of the laser surveying system according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram of an optical device of a main body according to the embodiment.

FIG. 4 is a block diagram (1) of the laser surveying system according to the embodiment of the present invention.

FIG. 5 is a block diagram (2) of the laser surveying system according to the embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional laser surveying system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Light-emitting means 12 Rotary scanning means 13 Light-receiving means 14 Encoder 15 Control means 16 Light-receiving amount detecting means 21 Target

Claims (6)

[Claims] 1. A light emitting means for emitting laser light, a rotary scanning means for projecting and scanning the laser light toward a target placed on an object to be measured, and a light receiving means for receiving the laser light reflected by the target. A laser surveying system having means for acquiring position information of the target from the received laser light, wherein the control means emits the light when scanning within a predetermined angle range including the direction of the target. A laser surveying system characterized by causing the means to emit light. 2. The laser surveying system according to claim 1, wherein, when there are a plurality of targets, the predetermined angle range is an angle range including directions of the plurality of targets. 3. The laser surveying system according to claim 1, wherein when the plurality of targets are provided, the predetermined angle range is a plurality of angle ranges for each direction of the plurality of targets. 4. The apparatus according to claim 1, wherein said control means causes said rotary scanning means to rotate and scan the laser light in a direction of 360 degrees in advance, and said rotation when said light receiving means receives said laser light. From the scanning direction of the scanning means,
A laser surveying system for detecting a direction of the target. 5. A light emitting means for emitting laser light, a rotary scanning means for projecting and scanning the laser light toward a target placed on an object to be measured, and a light receiving means for receiving the laser light reflected by the target. Means, and a laser surveying system having control means for acquiring positional information of the target from the received laser light, wherein the control means detects an amount of laser light received by the light receiving means, and And changing the amount of laser light emitted by the light-emitting means in accordance with the condition. 6. A laser surveying system according to claim 5, wherein said control means reduces the light emission amount of the laser light emitted by said light emitting means so that said light reception amount becomes a predetermined value or less. .