JPS6348282B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser-based leveling method that utilizes the straightness of a laser beam to use a laser beam from a light emitting source on a fixed point as a reference for the level or altitude at the point where the laser beam is received.

To give a specific example, when excavating a drainage ditch on a horizontal surface or with an extremely gentle slope in a vast area such as a farm,
Extremely high-precision height measurement means are required, and as an effective method for this purpose, the use of the straightness of laser beams emitted from a fixed point has been proposed and is being put into practical use. That is, this is a method in which a laser beam is emitted horizontally or at a desired angle from a fixed point, and the above-mentioned excavation work or the like is performed along the laser beam or parallel to it.

In this way, the straightness of laser beams is being used as a standard for slope and elevation in construction work and other height measurements that require extremely high precision.

However, in this conventional method, the laser beam emitted from the light source was used as an absolute reference for slope and altitude regardless of the distance between the laser light source and the light receiving point, so the distance from the light source was large. As you can see, the drawback was that the height measurement error increased.

In other words, as is clear from the above example, when forming horizontal surfaces or sloping grooves on the earth's surface, and when guiding moving objects, it is best to use standards from various places on the earth's surface as standards for elevation and slope. Although this should have been necessary, the conventional method simply uses a laser beam that travels straight without taking into account the spherical shape of the earth, so as the distance from the light source increases, the reference using the laser beam becomes less ground-based. It had the drawback of deviating from the true standard at each point on the surface.

To resolve this inconvenience, it would be possible to arbitrarily correct the distance information from the light emitting source by transmitting the distance information from the light source to the moving object in addition to the leveling information by the laser beam. In order to communicate this information, there was a problem that required separate wireless transmission and reception facilities.

The present invention does not require dedicated special facilities for transmitting distance information to a moving object, and the present invention does not require the use of a laser beam that is inevitably used for leveling.
The purpose is to be able to convey distance information by devising light reception.

In order to achieve the above object, the present invention provides the above-mentioned leveling method using a laser, in which (a) the laser beam is sequentially scanned in different azimuth directions, and (b) the laser beam emitted from the light emitting source is
The laser beam is emitted at a blinking period corresponding to the deviation angle of the emitting direction with respect to a preset reference direction, and (c) the moving body that receives the laser beam has light receiving positions set at three horizontally distant locations. (d) Determine the distance between the light emitting source position and the light receiving position based on the azimuth information based on the flashing cycle obtained from the laser beam received at each light receiving position and the emission direction of the laser beam with respect to each light receiving position. Leveling for correcting the curvature of the earth's surface using a laser, characterized in that the reference by the laser beam is corrected based on the distance measured in (a) to (d) above and the diameter of the earth. This paper proposes a method.

Because of these features, the method of the present invention allows highly accurate height measurements that are unaffected by the roundness of the earth's surface, no matter how far the light receiving position is from the light emitting source, without using a separate distance information transmission means. This can be done by effectively utilizing laser beams without the need for laser beams, and this also has the effect of dramatically increasing the range in which a single laser light source can be used compared to conventional methods. be.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a first embodiment of the present invention, which is a method for changing the vertical emission angle of a laser beam in a laser light source 1. In FIG. In this case, the height of the laser light source 1 is H, the emission angle of the laser beam with respect to the vertical direction is h, the height of the light receiver 2 at the light receiving position is h, the distance between the light source 1 and the light receiver 2 is l, and the angle of the laser beam with respect to the vertical direction is If the radius is R, then from the cosine theorem, =cos ^-1 (R+H) ² +l ² -(R+h) ² /2l(R
+H) ......(A) There is a relationship. This formula (A) means that if the distance l is known, the firing angle to keep the height h constant can be calculated.

This is effective in improving height measurement accuracy when forming grooves of a predetermined depth or slope on a predetermined course 3 as shown in Figure 2, or when leveling the ground. Available. That is, a laser receiver 2 is installed on a work vehicle (mobile object) such as a bulldozer, the work vehicle is driven so as to receive the laser beam at a certain height h based on its own standard, and the laser light source side is connected to the work vehicle. The distance l is measured using a radar or a method as described below, and the angle is calculated using the above formula using this distance l and the previously known height h.
Calculate from (A) and change the laser emission angle up or down according to that angle, thereby correcting the reference by the laser beam.

FIG. 3 shows a second embodiment of the present invention, in which the reference is corrected by calculation on the side receiving the laser beam while keeping the vertical angle of the laser beam constant (for example, π/2).

That is, in this case, the receiver 2 receiving the laser beam
If the height of is h', the following equation holds from the relationship shown in FIG.

h'=√(+) ² + ² −R (B) Here, the symbols R, H, and l are the same as in the previous embodiment. Therefore, at the light receiving point,
Instead of using the height H of the laser emitting point as the standard as in the past, by using the height h' corrected by the distance l between the two points according to equation (B) above, it is possible to measure the height of the earth's surface. It is possible to perform highly accurate height measurements that are not affected by the roundness of the surface.

Next, a more specific example, ie, a third example, will be described using FIG.

In this embodiment, by rotating the laser beam within a horizontal plane in the light emitting source 1, it is possible to measure not only the height but also the position of a moving vehicle at the same time.

First, a method for measuring the position of a moving object will be explained. 3 arranged on a moving body at a constant interval d
Detecting the azimuth angles θ ₁ , θ ₂ , θ ₃ with respect to the light beam A at the positions B, C, and D of the photoreceivers 2 . . . by means described later,
The position of the moving body is detected from these angles. That is, in Fig. 4, since there are relationships α ₁ = θ ₂ −θ ₁ and α ₂ = θ ₃ −θ ₂ , the distance between AC is l, ∠ABC=
Applying the law of sine to △ABC and △ACD as x, d/sinα ₁ = l/sinx, d/sinα ₂ = l/sin (α ₁ +
This method uses the fact that two equations (α ₂ −x) are obtained to find l.

Hereinafter, the specific configuration will be sequentially explained using FIG. 5.

A laser emitting semiconductor 4 is used as a laser emitting body in the laser emitting source 1, and the semiconductor 4 is rotated around a vertical axis by a motor 5, so that the laser beam scans in a horizontal plane. Further, in order to carry information indicating the direction in which the laser beam is being emitted, the laser beam is modulated to change the blinking period in the following manner.

That is, the rotary encoder 6 connected to the motor 5 outputs the direction in which the laser beam is emitted, and the output of the rotary encoder 6 is output from the D/A.
The signal is inputted to a V-P converter 8 via a converter 7, and the semiconductor 4 is operated by the output of the V-P converter 8. In addition, V-P converter 8
is composed of an integrator, a comparator, a buffer amplifier, etc.

On the other hand, the three light receivers 2 provided on the moving body on the light receiving side each have a plurality of laser light receiving elements 10 arranged above and below, and the height at which the laser beam is received is It is configured to detect. The three light receivers 2... each have the same configuration. That is, in each light receiver 2, the output of each light receiving element 10... is passed through a bandpass filter 11... and a waveform shaping comparator 11'...
The signal is inputted to the set terminal of the R-S flip-flop 12 and the OR gate 13 via the RS flip-flop 12. The outputs Q of the R-S flip-flops 12 are input to an encoder 14, and the encoder 14 outputs the receiving height of the laser beam. On the other hand, the OR gate 13 outputs a pulse corresponding to the blinking modulation of the laser beam, and by measuring the period of this pulse, the direction in which the laser beam is emitted is measured. This may be measured by applying the output of the encoder 14 as a code signal. In the former method, the output of the OR gate 13 is input to a counter 15 that counts the number of blinks of the laser beam input to the light receiving element 10 and a time measurement circuit 16 that measures the time from the first pulse to the last pulse. ing. Note that in the latter case, the signal will be input to the signal detection circuit. The flip-flop 161 of this time measuring circuit 16 outputs a high level at the first pulse, and the gate 162 is opened. Counter 163 counts clock pulses φ while gate 162 is open. Another counter 164 is reset by the pulse of the comparator 11', so it counts the clock pulses φ after the last pulse of the comparator, and when it reaches a predetermined value, it outputs a negative signal and resets the flip-flop 1.
By resetting 61, gate 162 is closed. Therefore, the time is measured by subtracting a certain period of time from the value of the counter 161.

Therefore, by inputting all the outputs of the encoder 14, the counter 15, and the time measuring circuit 16, which output the height of the laser beam received by each photoreceiver 2, into the computer 17, This computer 17 calculates the position and height based on the above formula, and is applied to controlling the moving object so that it is at a desired position and height.

In this example, if some information is obtained in advance about the range of existence of the moving body on the light receiving side, the laser beam can be emitted in all directions (360 degrees).
Measurement accuracy can be improved by configuring to scan only within that range without scanning over the entire range. To do this, a transmitter is installed on the receiving side,
The azimuth angle θ of the received laser beam is transmitted to the emitting side, and the emitting side receives the signal and calculates the azimuth angle θ.
It may be configured to fire only in the vicinity.

[Brief explanation of drawings]

The drawings illustrate an embodiment of the leveling method for correcting the curvature of the earth's surface using a laser according to the present invention. Principle explanatory diagram of the embodiment, No. 4
The figure is a diagram explaining the principle of the third embodiment, and FIG. 5 is a schematic circuit diagram thereof. 1... Laser emission source, 2... Light receiving position, l...
...Distance between 1 and 2, R...The diameter of the earth.

Claims (1)

[Scope of Claims] 1. In a laser-based leveling method that utilizes the straightness of the laser beam to use a laser beam from a light emitting source 1 at a fixed position as a standard for the level or altitude at a position 2 that receives the laser beam, ) The laser beam is sequentially scanned in different azimuth directions, and (b) The laser beam emitted from the light emitting source 1 is emitted at a blinking period corresponding to the deviation angle of the emission direction with respect to a preset reference direction. (c) For the moving object that receives the laser beam, light receiving positions 2 are set at three horizontally separated locations, and (d) the blinking cycle obtained from the laser beam received at each of the light receiving positions 2 is determined. Direction information by
From the emission direction of the laser beam to each light receiving position 2, the position of the light emitting source 1 and the light receiving position 2 are determined.
, and corrects the reference by the laser beam based on the distance l measured in (a) to (d) above and the diameter R of the earth. A leveling method that corrects the curvature of the Earth's surface.