JPH03200086A - Laser receiver - Google Patents

Abstract

PURPOSE:To eliminate the impossible state of measurement caused by the dead angle of an optical sensor with simple configuration by receiving laser beams to be oscillated and sent by three optical sensors arranged at mutually different positions while turning the laser beams at the same angular velocity from a laser oscillation side device. CONSTITUTION:When a laser beam CW to be outputted and turned from a laser lighthouse 51 arrives at a reference line, a reference surrounding information signal is outputted with non-directivity. This signal is received at an input part 7 and sent out to a time counter 9. After the lapse of short time from the output of this reference surrounding information signal, the turning laser beams CW are continuously received by respective optical sensors S1, S2 and S3 of a light reception part 4 and light reception signals are set out to the input part 7. The waveform of the light reception signal is shaped and the signals are successively sent out to the time counter 9. On the other hand, the time counter 9 counts time from the reception of the reference surrounding information signal to the input of the light reception signals from the respective optical sensors S1, S2 and S3 and sends a counted result to an arithmetic control part 10. The control part 10 executes prescribed arithmetic operation, calculates a reference azimuth and the azimuth angles of the respective optical sensors S1, S2 and S3 and calculates the position of a traveling object 52.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a laser light receiving device, and is particularly suitable as a light receiving device in a position measuring system for a moving object, etc., which uses a so-called laser lighthouse as a laser oscillation device. The present invention relates to a laser receiving device.

[Background technology]

Recently, various methods for measuring the position, direction, etc. of unmanned moving objects have been studied in various fields in order to automate the positioning and guidance of unmanned moving objects using laser lighthouses. A position and direction measurement system using such a laser lighthouse can be used, for example, for ships passing through straits or ports, aircraft running or taxiing in airports, mobile work machines in factories and farms, construction work machines, construction work robots, etc. It can be used for monitoring and guidance.

FIG. 7 shows an example of a position and orientation (heading) measurement system using this laser lighthouse.

In this figure, numeral 51 indicates a laser lighthouse installed at reference point 0, numeral 52 indicates a moving object, arrow H indicates the traveling direction of moving object 52, and arrow N indicates a reference direction (for example, north). shows.

The laser lighthouse 51 is assumed to rotate its output laser light within the same horizontal plane at a constant angular velocity.

On the moving body 52, optical sensors S II+ Sl□, Sl, for receiving laser light are arranged at positions forming the apexes of a triangle. These optical sensors S I l +
SIz and S13 are fixed on the moving body 52. Point M
indicates the inner center of the triangle formed by these optical sensors S ++ S 1zS B.

In this figure, the elements that determine the position of the moving object 52 are the distance R between the reference point O and the point M (which is taken as a representative point of the moving object 52), and the distance between the arrow N indicating the reference direction and the line segment OM. angle θ
1. The element that determines the heading is the angle θ between arrow H and arrow N.
3 can be easily determined from θ3=θ1+θ2 if the angle θ2 between the extension of the line segment OM and the arrow H is known.

These elements R1θ1. As a method for determining θ2, for example, a method is constructed that includes an optical sensor that receives a laser beam on the reference azimuth (indicated by arrow N) line, and upon receiving the detection signal of this optical sensor, outputs a reference azimuth information signal wirelessly. Based on the time difference between the output time of this reference direction information signal and the light reception time of the three optical sensors S11+SI□, Sl fixed on the moving body 52, the laser Utilizing the fact that the angular velocity of the laser beam of the lighthouse 51 and the positional relationship of each optical sensor are known,
For example, from the angular velocity ω of the laser beam, the angle θ4 shown in FIG.
．． Since θ can be easily calculated, R2θ1. can be calculated geometrically and analytically (using trigonometric functions, etc.). θ2 has been calculated.

For example, there is Japanese Patent Application Laid-Open No. 56-114773.

[Problem that the invention sought to solve]

However, in the above conventional example, as shown in FIG. 9, a laser lighthouse 5I and two optical sensors 31! +3
13 are lined up in a straight line, the previous optical sensor 311 becomes an obstacle and prevents the laser beam from reaching the optical sensor S + Z (creating a blind spot), which causes the inconvenience that measurement may not be possible. .

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a laser light-receiving device that can overcome the disadvantages of the prior art and, in particular, can eliminate the above-mentioned measurement failure state caused by the blind spot of the optical sensor with a simple configuration.

[Means to solve the problem]

In the present invention, a light-receiving section (all having three optical sensors) arranged at different positions to receive laser beams oscillated and sent while rotating at the same angular velocity from a laser oscillation side device, and each optical sensor It is equipped with a timer for measuring the difference in light reception time between the two, and an arithmetic control section attached to the output stage of the timer.

Further, the light receiving section is provided with a light receiving section driving means for rotating the light receiving section. The arithmetic control unit has a relative angle calculation function that calculates the relative angle that each optical sensor makes with the laser oscillation side device as the center based on the light reception time difference and the known turning angular velocity of the laser beam, and The structure includes a stepping control function for reciprocating the light receiving section by a predetermined angle via the light receiving section driving means when the relationship does not satisfy a certain condition. This is an attempt to achieve the above-mentioned purpose.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

This embodiment relates to a position measuring system for a moving body using a laser light receiving device according to the present invention as a light receiving device.

FIG. 2 shows a laser lighthouse 51 as a laser oscillation side device.
, and a moving body 52 that is the object of measurement.

The laser lighthouse 51 has a function of oscillating laser light (CW) and rotating the laser light (CW) clockwise at a constant angular velocity ω within the same horizontal plane. This laser lighthouse 51 actually includes a laser oscillator, a mirror, a rotating table, etc. (not shown).

On the movable body 52, there is a triangular support plate 3 and this support plate 3.
Three photosensors s, , S2 . A light receiving section 4 consisting of S3 and a support column 5 that rotatably supports the light receiving section 4 are provided. Each optical sensor 5IS2. As Sz, in this embodiment, a so-called omnidirectional type having a field of view of 360 degrees is used. The support column 5 includes optical sensors St,
One end is implanted in the support plate 3 with its center located at the inner center M (see FIG. 3) of the triangle S+StS3 formed by StS. Further, the support column 5 forms a part of the light receiving unit driving means 6 (see FIG. 1), and the other end is pivotally supported by a movable body 52, and the support column 5 is connected to a power transmission gear (not shown) built in the movable body 52. It is designed to be rotated by a motor (not shown) as a drive source via a mechanism.

In this embodiment, these support columns 5. power transmission gear mechanism,
A light receiving unit driving means 6 is constituted by a motor or the like.

As shown in FIG. 1, an input section 7 is attached to the output stage of the light receiving section 4, and a time counter 9 as a time measuring means is attached to the input section 7.

Furthermore, an arithmetic control section 10 is also provided at the output stage of the time counter 9. In this embodiment, these light receiving sections 4. The time counter 9 and the arithmetic control unit 10 constitute a laser light receiving device 1, and the entire laser light receiving device 1 is mounted on a moving body 52.

The input unit 7 shapes a reference direction information signal (FM signal) sent from a reference sensor device (described later) and a received light signal sent from optical sensors S, , S, , S into digital waveforms, respectively. Waveform shaping circuit (not shown)
and outputs each shaped signal to the time counter 9 at the next stage. The time counter 9 starts measuring time after receiving the reference azimuth information signal from the input section 7, and each optical sensor s, , St sent from the input section 7.

Time 1+, 12, t until the light reception signal of S is input
. After each time data is collected, it is sent to the arithmetic control section 10. The calculation control unit 10 takes in the time data that is the output of the time counter 9, performs predetermined calculations based on it, and calculates the reference azimuth N (see FIG. 3) and the azimuth angle of each optical sensor Sl, StS. The position of the moving body 52 (the distance between the light receiving unit 4 and the laser lighthouse 51 and the azimuth of the moving body) is calculated as described below. In addition, the calculation control unit 10 controls each optical sensor St, SzS to control the laser lighthouse 5 based on the light reception time difference and the known turning angular velocity ω of the laser beam.
1 as the center (relative angle calculation function), if the relationship between the calculated relative angles does not satisfy certain conditions described later, the light receiving part driving means 6 moves the light receiving part 4 to a predetermined angle ( It has a stepping control function that allows reciprocating rotation (for example, 30°).

Furthermore, this arithmetic and control unit 10 is also provided with front/rear wheel drive means 11 for steering the front wheels 12A and rotationally driving the rear wheels 12B. The arithmetic control section 10 also controls the steering of the front wheels 12A and the rotation of the rear wheels 12B via the front/rear wheel drive means 11.

Next, the principle of position measurement of the moving body 52 according to this embodiment will be explained based on FIG. 3.

In FIG. 3, a laser lighthouse 51 is installed at a reference point 0 for measurement.

Laser light (CW) is output from this laser lighthouse 51 and is rotated at a constant angular velocity ω in a horizontal plane.

A reference sensor device (not shown) is installed on the reference direction (indicated by arrow N) of the laser lighthouse 51. This reference sensor device includes an optical sensor that receives laser light and an FM oscillator, and receives the detection signal of the optical sensor and wirelessly outputs a reference direction information signal (FM signal). be.

In this FIG. 3, the angle θ7. θ7. θ is the optical sensor S
The azimuth angles of +, Sz, and Si are shown, respectively, and arrow H shows the traveling direction of the moving body 52. Also, point M is optical sensor S
, ,S, ,S, indicates the incenter of the triangle.

In this figure, the elements that determine the position of the moving object 52 are the distance R between the reference point O and the point M (which is taken as a representative point of the moving object 52), and the distance between the arrow N indicating the reference direction and the line segment OM. angle θ
, and.

Here, how to obtain the distance R and the angle θi will be briefly explained.

Assuming that the turning angular velocity ω (constant) of the laser beam CW is known, the azimuth angle θ3. θ2°θ is determined as follows.

θ,=ωt1 ・・・・・・■
θ2=ωtz ・・・・・・
■θ3=ωt3 ・・・・・・
■Also, with reference point 0 as the center, optical sensor Sl and 52S1
and S, , the angle θ4θ2 . formed by Si and Si, respectively. θ6 is θ4=θ2−θ, ・・・・・・■
θ, -θ3-θ1 ・・・・・・■
θ6=θ3−θ2 ・Old・・Determined by ■.

On the other hand, the reference point 0 and each optical sensor S, , S2 . s.

The distance from θ1 to θ and the relationship between each optical sensor (the lengths and angles of the sides of the triangle S+SzSi are known) can be easily calculated using the law of sine. Here, the specific calculation formula is omitted.

In this way, the position (polar coordinates) of each optical sensor is determined, and based on this, the coordinates of the inner center M, that is, the distance i! ! iIR and angle θ are determined.

Next, the principle of stepping control, which is the main function of the arithmetic control section 10 in this embodiment, will be explained with reference to FIGS. 4 and 5.

The arithmetic control unit 10 uses the above 0.0 formula to calculate θ6. as shown in FIG. Calculate θ6.

And these θ3. θ, is LSI θ6/θ, 1kuH...■ (Here, L,
H is a darkness value) is satisfied, and if not satisfied, a motor (not shown) constituting the light receiving unit driving means 6 is controlled to move the light receiving unit 4 at a certain angle (here, 30°). ) By rotating in either direction, it is possible to avoid aligning the two optical sensors in a straight line.

That is, in the above equation 0, the state of L=O means that the optical sensors St, S
z and the laser lighthouse 51 are aligned in a straight line, and the state of H=1 corresponds to the state where the optical sensors SI, Si and the laser lighthouse 5
1 are lined up in a straight line. For this reason, for example, if the threshold value L = 0.2H = 0.8 is set and the condition of the above formula 0 is no longer satisfied, either two sensors can be aligned by rotating the light receiving section 4 by 30 degrees. You can avoid standing in line.

In this case, two states are sufficient for step rotation, so in this embodiment, reciprocating rotation is performed within a range of 30 degrees. In FIG. 5, the moving body 52 is (A)→
The light receiving unit 4 is shown reciprocatingly rotating within a range of 30° while proceeding from (B) to (C).

Next, the overall operation of this embodiment will be explained.

When the laser light CW output from the laser lighthouse 51 installed at the measurement reference point 0 and rotating in the same horizontal plane reaches the reference line, the reference sensor device outputs a reference direction information signal in an omnidirectional manner.

This reference direction information signal is received by the input section 7, waveform-shaped into a digital signal, and then sent to the time counter 9. Then, after a minute time has elapsed since the output of this reference direction information signal, each optical sensor S1'r Si + S of the light receiving section 4
The laser beams CW rotating at i are received one after another and a light reception signal is sent to the input section 7. The input section 7 shapes the waveform of the light reception signals sent from each of the optical sensors S, , S, .

On the other hand, the time counter 9 starts time measurement after receiving the reference direction information signal, and calculates the time t+, tz until the light reception signals of the respective optical sensors S+, St, and Ss sent from the input section 7 are input. , t*. Then, each time data is sent to the arithmetic control section 10 in its entirety. The calculation control unit 1o takes in the time data that is the output of the time counter 9, performs predetermined calculations based on it, and determines the reference direction N (see Fig. 3) and the directions of each optical sensor St, St, Ss. The angle is determined, and the position of the moving body 52 (
The distance R between the light receiving unit 4 and the laser lighthouse 51 and the azimuth angle of the moving object (0.4) are calculated.

In this case, if the condition of equation 0 is not satisfied, the arithmetic control section 1o controls the motor (not shown) constituting the light receiving section driving means 6 as described above to move the light receiving section 4 to 30''. The moving body 5 is rotated in either direction so that the two optical sensors are not aligned in a straight line.
Calculate position 2. Next, in the calculation control unit 1o,
Based on this calculated result, the movement of the moving body 52 is controlled via the front/rear wheel drive means 11.

As explained above, according to the first embodiment, the moving body 5
The optical sensors St, S2 . Any two of S3 are laser lighthouses 5
1, the arithmetic control unit 10 detects this and rotates the light receiving unit 4 in steps by a certain angle (for example, 30°) within the horizontal plane, so that the optical sensors St and S
2. It is possible to avoid having any two of S3 lined up in a straight line. As a result, three optical sensors St, 5zS
3 can always receive laser light,
It is possible to almost completely avoid the inability to measure due to the blind spot of the optical sensor, which has been a problem in the past. Further, since the step rotation is a constant angle (for example, 30°), the configuration of the light receiving unit driving means 6 and its control method may be simple.
The light receiving unit driving means 6 can be configured with a simple gear mechanism and a motor, and furthermore, since the rotation range of the light receiving unit 4 is narrow, a slip ring is used for continuous electrical connection for rotation. Since this is not necessary, it is possible to improve the durability of the rotating part.

In the above embodiment, the laser lighthouse 51, which is the laser oscillation side device, was installed at the reference point, and the laser light receiving device 1 was mounted on the moving body 52. However, on the contrary, the laser lighthouse 51 was mounted on the moving body 52. However, it is also possible to measure the position of the moving object by installing the laser light receiving section W1 at a reference point.

Furthermore, the present invention is not limited to the above embodiments, but also includes the following modifications.

That is, a special laser lighthouse 31 that oscillates and rotates a laser fan beam (LFB) as shown in FIG. 6(1) is used as a laser oscillation side device, and a light receiving section having a three-dimensionally arranged optical sensor is used. 9 For example, as shown in FIG. 6(2), four optical sensors s, s, s3 . s
It is possible to construct a light-receiving device in the same manner as in the above embodiment using the light-receiving portion 34 in which the light-receiving portions 34 are arranged such that , are located at each vertex of a tetrahedron.

In this case as well, there are four optical sensors S, , S21 3
When any two of 31 Sa are aligned with the laser lighthouse 31, the light receiving section can be rotated as a whole around the support column 5 to avoid creating a blind spot in the optical sensor.

〔Effect of the invention〕

Since the present invention is configured and functions as described above, according to the present invention, the light receiving device according to the present invention is mounted on a moving body as in the above embodiment, and the laser oscillation side device is installed at a reference point, and the moving body When performing position measurement, etc., just before any two of the optical sensors that make up the light receiving section are aligned with the laser oscillation side device, the control section functions to position the light receiving section entirely within the same plane. This can be avoided by rotating the angle (e.g. 30°) in steps, allowing all optical sensors to always receive laser light, and almost completely avoiding measurement failures due to blind spots of optical sensors. can do. Further, since the step rotation is a predetermined angle (for example, 3°), the configuration of the light receiving unit driving means and its control method may be simple. For example, the light receiving unit can be driven using a simple gear mechanism and a motor as in the above embodiment. Alternatively, the light receiving unit driving means can be constructed using a simple gear mechanism and a solenoid. Furthermore, since the rotation range of the light receiving part is narrow, there is no need to use a slip ring to continuously connect electrical connections for rotation, which is unprecedented in that it is possible to improve the durability of the rotating parts. An excellent laser light receiving device can be provided.

6... Light receiving unit driving means, 9... Time counter as time measurement means, 10... Arithmetic control unit, 31.51... Laser oscillation side device Laser lighthouse as, 52...Moving object, St, S
t, S3. S4... Optical sensor, CW...
・Laser light, LFB... Laser fan beam.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a laser light receiving device according to a first embodiment of the present invention, and FIG. 2 is a block diagram showing a laser lighthouse and a moving body as a measurement target that constitute a position measurement system according to the first embodiment. 3 is an explanatory diagram showing the principle of measurement in the first embodiment; FIGS. 4 and 5 are explanatory diagrams illustrating the principle of stepping control of the arithmetic control section in the first embodiment; Figure 6 is an explanatory diagram showing a modified example, Figures 7 to 8
The figure is an explanatory diagram showing a conventional example, and FIG. 9 is a diagram for explaining problems in the conventional example.

Claims (2)

[Claims] (1) a light receiving section having at least three optical sensors disposed at different positions that receive laser beams oscillated and sent while rotating at the same angular velocity from a laser oscillation side device; A timing means for measuring the time of light reception;
an arithmetic control section attached to the output stage of the timekeeping means; a light-receiving section driving section for rotating the light-receiving section is attached to the light-receiving section; a relative angle calculation function that calculates the relative angle that each optical sensor makes with the laser oscillation side device as the center based on the turning angular velocity of the light receiving section; A laser light-receiving device characterized by having a stepping control function for reciprocating the light-receiving section by a predetermined angle via a driving means. (2), the calculation control unit extracts any two of the calculated relative angles and calculates the absolute value of their ratio, and if this absolute value is a value outside a predetermined range, 2. The laser light receiving device according to claim 1, wherein said stepping control is performed.