JPS62187271A - Position measuring method for vehicle - Google Patents

Abstract

PURPOSE:To measure the positions of plural vehicles based upon two reference positions with high accuracy by transmitting azimuth information along with laser light emitted by laser light emitting devices placed at the two reference positions and rotating them in a horizontal plane at a constant speed. CONSTITUTION:The laser light emitting devices 65 and 66 rotate in the horizontal plane at the constant speed at the two reference positions in such a limited area that the direction of a line connecting the two reference position faces in a reference direction, e.g. north, and also emit laser beams which are pulse- modulated with the azimuth information. Then, laser light receivers 63 and 64 which are mounted at prescribed positions on the vehicles 61 and 62 whose positioned are to be measured receive the laser light beams to obtain two pieces of azimuth information on the vehicles 61 and 62. The positions of the vehicles are computed by position arithmetic units mounted on the vehicles from the pieces of azimuth information and obtained position coordinates are sent from radio communication equipments 67 and 68 to a vehicle position controller 71.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a method for measuring the position of a vehicle, and is particularly suitable for measuring the position of a construction vehicle at a civil engineering work site where the vehicle travel path changes frequently and the road surface is not leveled. It is suitable for use.

(Prior Art) Conventional position measurement methods for running vehicles are classified as follows. That is, (A) a method in which a traveling vehicle detects its position using an external support facility.

(A)-(1) Fixed route method...Guiding the vehicle by a cable buried in the running track or optical tape fixed on the running track, or by a laser beam emitted along the running track. A method of guiding a moving vehicle.

(A) - (2) Semi-fixed route method (old): A method of guiding vehicles using marks placed on the road surface of the vehicle.

(A)-(3) Free route method - Old method: While measuring the direction and distance from the reference point of the external support facility to the traveling vehicle,
It is a method of guiding a free path, and uses radio waves, lasers, or ultrasonic waves as the measuring means, and there are the following two methods of measuring. That is, (A) = (3) - (i) Arc method...In Figure 8 (a), a and b are two reference points on the ground, and p is the point of the moving vehicle whose position is being measured. It's the location.

- As an example, a case using radio waves will be explained.

Radio waves are transmitted from point P and received at points A and B.

If you reply at the same time as receiving and receive this at point p.

The position of point p is determined by measuring the time taken for the radio waves to travel back and forth between pa and pb.

(A) - (3) (ii) Hyperbolic method...
- Fig. 8 (In BL, a, b, and C are three reference points on the ground, and p is the position of the traveling vehicle that is the object of position measurement.) - As an example, the case where radio waves are used will be explained.

If radio waves are transmitted at points a and b at the same time T0 and received at point p at times T and Tb, the following equation holds true, where ■ is the propagation speed of the radio waves.

Distance between pa L, = V (T, T O)
−・−fllpb distance L b = V (T
b T a) -...(2) Therefore Lll Lb
=V(T-Tb)--(3) According to formula (3), T
, -T, and then -L.

can be calculated. Since the locus of a point whose distance from two fixed points is constant is a hyperbola with the two fixed points as focal points, point p is one hyperbola with focal points at points a and b (see Figure 8). 5abp) of b). If similar measurements are made for points a and C, point p will be a hyperbola with focal points at points a and C (S, cp in Figure 8(b)).
), and the position of point p is determined as the intersection of the hyperbolas 5abp and Sacp. (However, there are two points of intersection between the two hyperbolas, but the measurer only has to select one point that is close to the estimated position.) (B) Rotation of the wheels of the traveling vehicle without using external support facilities and mounting on the traveling vehicle A method for a traveling vehicle to independently measure distance and direction using a gyro (problem to be solved by the invention) At a civil engineering work site where construction vehicles are operated, (a) the route of the construction vehicle changes frequently; . (b) Among the position measurement methods described above (prior art), there is an adverse condition that the road surface for construction vehicles is not leveled.

The (A)-(1) fixed route method and the (A)-(2) semi-fixed route method cannot be used due to the condition that the route of the construction vehicle (a) changes frequently. In addition, in the above (B) position measurement method in which the traveling vehicle stands alone without using external support facilities, errors accumulate, so it is difficult to reach the civil engineering work site due to the condition that the road surface for construction vehicles is not leveled. Application is very difficult.

Of the position measurement methods described above (prior technology), the free path method (A)-(3) is practical at civil engineering work sites, but among the measurement methods, conventional methods using radio waves are Although it is suitable for long-distance and large-scale applications such as ships, it is expensive and its positioning accuracy is not very good. Additionally, there are the following problems with the measurement method.

(A) (3)-(i) The arc method can only perform positioning of one construction vehicle with respect to two reference points.

(A) (3) (ii) The hyperbolic method is capable of positioning multiple construction vehicles, but it requires three reference points and between the reference points (points a and b in Figure 8(b)). and a
This method has the problem of being complicated and expensive because it requires synchronization at points (point C and point C).

In addition, the method of position measurement using laser light uses the laser light as a positioning medium and uses the geometric structure of the laser receiver to perform positioning, so there are requirements for the mechanical accuracy of the laser receiver. The problem is that the method is very strict and difficult to put into practical use.

(Means and effects for solving the problem) The present invention has been made in view of the above points, and the present invention has been made in view of the above-mentioned points.
A laser beam emitted from a laser emitter placed at a reference position is loaded with azimuth information and rotated at a constant speed in a horizontal plane.

The azimuth information placed on the laser beam is, for example, 2'' for 360°.
It is expressed as a divided n-bit binary number.

In addition, by installing one laser receiver that can receive light in all directions on the vehicle that is attempting to measure one position and receiving the laser beam, it is possible to measure the direction of the line connecting the two reference positions, in this case north. The angles α and β from can be obtained with an accuracy of 360°/2″ and the position of the vehicle can be calculated.

In this way, according to the present invention, it is possible to measure the positions of a plurality of vehicles with respect to the two reference positions, and the laser receiver only needs to be able to receive laser light.
Unlike the prior art, it is possible to measure the position of the vehicle with high precision without depending on the geometrical structure of the light receiver.

(Example) Examples of the present invention will be described below based on the drawings.

FIG. 4 is a schematic diagram of a specific example of a laser emitting device 40. A laser emitting device 41 is rotatable in a housing 44 having two legs 45 via a turntable 42 rotated at a constant speed by a motor 43. It's like a pivot point. 0 indicates the center line of rotation of the laser emitter 41.

Further, the laser emitter 41 has a built-in laser light modulator (not shown). This laser emitting device 40 has nine legs 4
By adjusting the length of the laser beam 5, the laser beam emitter 41 is installed on the ground so that its rotational center line O is vertical, so that the laser beam rotating twice forms one horizontal plane.

Figure 2 shows the above laser luminous intensity AI! ! 3 is an explanatory diagram of a specific example of a method of adding azimuth information to the modulated laser light emitted from the built-in laser emitter 41. FIG. In the figure, the upper N direction indicates north, and 360 degrees counterclockwise from the N direction is divided into 211 equal parts (the case of 210 equal parts will be explained below). For each equal division angle, start from the N direction. Expressed counterclockwise as a 10-bit binary number. For example, O degrees ~ 3
The range of 60/2I0 degrees is (0000000000),
The range from 360/2" degrees to 2 x 360/2" degrees is (0000000001), and in the same way, the angle from the N direction corresponds to a 10-bit binary number. Therefore, the range of each equal angle is 360/21
0 degrees #0.352 degrees, and azimuth information can be given to the laser beam with an accuracy of 0.352 degrees.

FIG. 3 is a concrete example of a time chart (timetable) of the pulse signal and the emitted laser light given to the modulated laser light emitted from the laser light emitter 41 with a built-in laser light modulator, and the horizontal axis is the time in both cases. shows. In the figure, (1) shows a clock pulse from a crystal oscillator forming a part of the modulator.

(2) is the start pulse given to the laser emitting part,
The clock pulse (1
) is 10 in this specific example (clock pulses that overlap with the start pulse are excluded from the count).

(3) was explained in FIG.

It is a pulse representing a 10-bit binary number corresponding to the azimuth angle, in this example (1010010001), that is, (657 to 658) x 360/counterclockwise from north.
This represents an angle of 1024 degrees = (230,977 to 231.328) degrees. (4) is a modulated laser beam that is emitted.

In order to define the pulse position for calculating the azimuth information in (3), a modulated laser beam is shown in which the azimuth information pulse in (3) is combined with the start pulse in (2).

FIG. 5 is a schematic diagram of a specific example of the laser light receiving device 50. In the figure, the laser light receiving section 51 is constructed by forming a light receiving element made of, for example, amorphous silicon into a plate shape into a regular n-prismatic prism (n≧3), and FIG. 9 shows a regular triangular prism. Since this laser light receiving section 51 may have any shape as long as it can receive light in all directions, it goes without saying that it may have a cylindrical shape in addition to a regular n-prism. This laser light receiving section 51
The light-receiving surface constituting the laser light-receiving device 50 is always vertical when mounted on a vehicle, regardless of the inclination of the vehicle or the unevenness of the ground.

It is placed on the attitude control device 52.

FIG. 1 is an explanatory diagram of the vehicle position calculation method of the present invention.

In the figure, 01 and 02 indicate the positions of the laser emitting device 40 installed at two reference points on the ground, and correspond to O in FIG. 4. still.

The direction of the line connecting 01 and 02 is OI and 0! pointing north! Set. P indicates the position of the laser light receiving device 50 installed on the vehicle whose position is to be measured, and corresponds to the axial center of the regular triangular prism of the laser light receiving section 51 in FIG. 5. 1st
In the figure, measure the length of 0,0□, set the midpoint of 0.02 as A, and set the orthogonal coordinate axis A-x with A as the origin and north as the y-axis.
y.

If the length of AP is R, and the angles that OlP, OzP, and AP make with the y-axis are α, β, and θ, respectively, a 9th-order equation holds true.

However, in formula 4), R is much larger than L.

From equations (4) and (5), the coordinates x and y of point P can be calculated using the following equations. That is, in equations (4) and (5) 2, L is known, and α and β can be obtained using the method explained in Figures 2 and 3, so θ and R can be calculated, and equation (6) The positions x and y of the vehicle can be determined by

FIG. 6 is a schematic explanatory diagram of a specific example in which the present invention is applied to a civil engineering work site. In the figure, 61 and 62 are both construction vehicles undergoing civil engineering work, and 63 and 64 are the laser receivers 50 explained in FIG. 5, both of which are installed at two points that serve as references for position measurement on the ground. The laser beams from the laser emitting devices 65 and 66 are received. still,
The laser emitting devices 65 and 66 are installed at the first point.
This corresponds to Ol and 02 in the figure.

67 and 68 are wireless communication devices mounted on construction vehicles 61 and 62, respectively, and communicate with a wireless communication device 69 connected to a vehicle position management device 71 installed in one work site management office 70. I am supposed to contact you.

FIG. 7 is a block diagram of a specific example of measuring the position of the construction vehicle 61 shown in FIG. The measured value is calculated by the on-vehicle position calculation device 72 to become the coordinates X and y of the vehicle position P (see FIG. 1), and is input to the vehicle position management device 71 from the wireless communication device 67 via the wireless communication device 69. It looks like this.

(Effects of the Invention) Since the present invention is constructed as described above, it is possible to avoid problems such as at a civil engineering work site where construction vehicles operate (a) where the vehicle travels frequently, and (b) where the vehicle travels on an uneven surface.

Even under these adverse conditions, simply installing laser emitting devices at two reference points makes it possible to easily and inexpensively measure the positions of a plurality of vehicles equipped with laser light receiving devices. Furthermore, since a single work site management office can grasp the location of multiple work vehicles over a wide area, it is possible to issue appropriate work instructions, greatly improving efficiency and ensuring safety for each work. Furthermore, it has the excellent effect of allowing unmanned work to be performed.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the vehicle position calculation method of the present invention, FIG. 2 is an explanatory diagram of a specific example of adding azimuth information to laser light, and FIG.
The figure is an explanatory diagram of a specific example of a pulse signal given to a laser beam and a time chart of the emitted laser beam, FIG. 4 is a schematic diagram of a specific example of a laser emitting device, and FIG. 5 is a specific example of a laser light receiving device. , FIG. 6 is a schematic explanatory diagram of a specific example at a civil engineering work site, FIG. 7 is a block diagram of a specific example of measuring the position of the construction vehicle 61 in FIG. 6, and FIG. ) and (b) are explanatory diagrams of the circular arc method and the hyperbolic method, respectively, of the free path method among the position measuring methods of the prior art. 40... Laser light emitting device, 50... Laser light receiving device. ol, 0□... Laser emitting device 4 placed at the reference position
0 rotation center line, P... position of the vehicle-mounted laser light receiving device 50.

Claims (1)

[Claims] At two reference positions within a limited area, it rotates at a constant speed in a horizontal plane and emits a laser beam that is pulse-modulated based on azimuth information, and is placed at a predetermined position on the vehicle whose position is to be measured. By receiving the laser beam with a laser light receiving device capable of receiving light in all directions, two pieces of azimuth information regarding the vehicle are obtained, and the position of the vehicle with respect to the two reference positions is measured. Vehicle position measurement method.