JPS62187270A - Position measuring method for vehicle - Google Patents

Abstract

PURPOSE:To measure the positions of plural vehicles based upon one reference position with high accuracy by sending azimuth information together with laser light emitted by a laser light emitting element placed at the one reference position and rotating it in a horizontal plane at a constant speed. CONSTITUTION:The laser light emitting device 40 rotates in the horizontal plane at a constant speed at the prescribed reference position in a limited area and emits a laser light beam which is pulse-modulated with the azimuth information. Laser light receivers 63 and 64, and 65 and 66 capable of receiving light in every direction are placed at prescribed positions on vehicles 61 and 62 whose positions are to be measured. Those light receives 63 and 64, and 65 and 66 receive laser light beams to obtain two pieces of azimuth information on the veicles 61 and 62. Further, azimuth measuring instruments mounted on the vehicles 61 and 62 obtain information on directions connecting the light receivers 63 and 64, and 65 and 66. The obtained pieces of information are processed by CPUs on the vehicles and sent as position information on the vehicles 61 and 62 to a vehicle position controller 71 from radio equipments 67 and 68.

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: A method of guiding the vehicle using marks placed on the road surface of the vehicle.

(A)-(3) Free route method: A method that guides a free route while measuring the direction and distance from the reference point of an external support facility to the traveling vehicle. Radio waves, lasers, or ultrasonic waves are used, and there are two measurement methods: That is, (A)-(3)-(i) Arc method...Figure 8 (
In al, a and b are two reference points on the ground, and p is the position of the vehicle whose position is to be measured.

- 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...
In FIG. 8(b), a, b, and C are three reference points on the ground, and p is the position of the vehicle whose position is to be measured. - As an example, a case using radio waves 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) −
-----(1) Distance between pb ML b = V (T
b −T o )−・−・(2) Therefore L −t,
b = v (T − T b )・----(31(
3) If T, -T, is measured by the formula, -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). 5-bp) above 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 5sbp and 5llcl. (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 (a) that the route of the construction vehicle changes frequently. In addition, the above (B) method of position measurement by autonomous vehicle without using external support facilities is as follows:
Since the errors accumulate, it is very difficult to apply this method to civil engineering work sites due to the condition that the road surface for construction vehicles is not leveled.

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) In the arc method, for two reference points,
Only one construction vehicle can be positioned.

(A) - (3) (ii) The hyperbolic method is capable of positioning multiple construction vehicles, but requires three reference points;
Furthermore, it is necessary to synchronize between the reference points (points a and b and points a and C in FIG. 8(b)), which is complicated and expensive.

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 problems) This invention has been made in view of the above points, and is based on the invention by adding azimuth information to a laser beam emitted from a laser emitter placed at one reference position. Rotate at a constant speed within the range. The azimuth information placed on the laser beam is expressed, for example, as an n-bit binary number obtained by dividing 360° into 2''.

In addition, by mounting two laser receivers capable of receiving light in all directions on the vehicle that is attempting to measure one position and receiving the laser beam, the angles α and β from the reference direction of the reference position, for example, the north direction, can be measured. of.

It can be obtained with an accuracy of 360°/2″.

The above vehicle is equipped with an azimuth measuring device (for example, a magnet), which makes it possible to obtain the angle θ between the north direction and the direction connecting the two laser receivers, and from these three data α, β, and θ. Calculate the position of the vehicle.

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

(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 rotatably mounted on a housing 44 having two legs 45 via a turntable 42 rotated at a constant speed by a motor 43. It is pivoted to. O indicates the rotation center line of the laser emitter 41.

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

FIG. 2 is an explanatory diagram of a specific example of a method for adding azimuth information to the modulated laser light emitted from the laser light modulator built-in laser emitter 41. In the figure, the upper N direction indicates north, and 360 degrees counterclockwise from the N direction is divided into 2" equal parts (the case of 2111 equal parts will be explained below). For each equal division angle, from the N direction Starting counterclockwise 1
Expressed as a 0-bit binary number. For example, O degrees ~ 360/
The range of 216 degrees is (0000000000), 3
The range from 60/2IO 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 equidistant angle is is 360/210
degree #Q, 352 degrees, and it is possible to give azimuth information 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 nine light receiving elements made of, for example, amorphous silicon into a plate shape into a regular n-prismatic prism (n≧3), and FIG. 1 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, O indicates the position of the laser emitting device 40 installed at a reference point on the ground.

Corresponds to O in FIG. Pl and P2 each indicate the positions of the two laser light receiving devices 50 installed on the vehicle whose position is to be measured, and correspond to the axial center of the regular triangular prism of the laser light receiving section 51 in FIG. 5. In Figure 1, the rectangular coordinate axis with the 0 point as the origin and the north position as the y axis is 0-xy, and P
+Pz is the length, the midpoint of P and P2 is p, the length of op is R, and the line segments OP, OP2. OPO and P, P2
A quadratic equation holds true if the angles formed by x with the y-axis are α, β, ψ, and θ, respectively.

However, in formula 5), R is much larger than L.

From equations (4) and (5), the coordinates x and y of the 20 points can be calculated using the following equations. That is, in equations (4) and (5), L is known, 1 α and β are obtained by the method explained in Figs. Since it can be found by

R and ψ can be calculated, and the positions X and y of the vehicle can be determined using equation (6).

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, 63.64° 65 and 66 are the laser receivers 50 explained in FIG. 5, and both are points that serve as reference points for position measurement on the ground. receives laser light from a laser emitting device 40 installed at 67
and 68 are radios mounted on construction vehicles 61 and 62, respectively, and communicate with a radio 69 connected to a vehicle position management device 71 installed in the second work site management office 70. It looks like this.

FIG. 7 is a block diagram of a specific example of measuring the position of the construction vehicle 61 shown in FIG. and θ (see Fig. 1) are calculated by the on-vehicle CPU 73 to determine the coordinates X and y of the vehicle position P0.
(See FIG. 1), and is configured to enter the vehicle position management device 71 from the radio device 67 via the radio device 69.

(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 such adverse conditions, simply installing a laser emitting device at one reference point makes it possible to easily and inexpensively measure the positions of multiple vehicles equipped with two laser 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 a laser beam, 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. 6 is a schematic 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. 72... Orientation measuring device, O... Reference position and decoy center line of the laser emitting device 40, P+, Pz... Position of the vehicle-mounted laser light receiving device 50. Patent applicant Komatsu Ltd. Agent (patent attorney) Osamu Matsuzawa Figure 4 Figure 5

Claims (1)

[Claims] At a predetermined reference position within a limited area, the laser beam 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 on the stand capable of receiving light in all directions, two pieces of azimuth information regarding the vehicle are obtained, and the two laser beams are received by a azimuth measuring device mounted on the vehicle. A method for measuring the position of a vehicle, characterized in that information on a direction in which devices are connected is obtained, and the position of the vehicle relative to the reference position is measured.