JPS62175813A - Method for guiding curved route of unmanned vehicle - Google Patents

Abstract

PURPOSE:To always guide an unmanned vehicle exactly on a guide line regardless of the forward or backward drive of the vehicle, by steering the vehicle so that the declination between the driving direction of the vehicle and the distribution direction of the guide line is set at '0' or the prescribed value in a drive system of the unmanned carrier. CONSTITUTION:An unmanned vehicle 2 contains three parts of sensors, e.g., the 1st sensors 11a and 11b, the 2nd sensors 12a and 12b, and the 3rd sensors 13a and 13b. These sensors detect simultaneously the displacement amounts of the vehicle 1 from a guide line 1 at there portional points. Then the curvature radius and the curvature center are calculated at the drive part of the carrier 2 on the line 1 according to the relation of alliance among those three detected displacement amounts. Then the displacement amount of the carrier 2 from the line 1 is calculated at the center point P4 based on said curvature radius and center. In addition, the declination between the driving direction of the carrier 2 and the tangent direction of the line 1 is calculated at the point P4 based on the displacement and the curvature center. Then the carrier 2 is steered so that the declination is set at '0'.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to unmanned forklifts and trolleys used in unmanned transportation systems in factories and warehouses, and unmanned regular dump trucks used in transporting mined materials in mines and the like. Furthermore, it also concerns a method of guiding unmanned vehicles such as autonomous (unmanned) vehicles, which are being considered for use on general roads, along guide lines arranged along the route, especially if the route is curved. The present invention relates to a guidance method that makes the steering of the unmanned vehicle more stable when the guidance line is also arranged in a curved line along the guidance line.

[Conventional technology]

To guide such an unmanned vehicle along a guide line, a sensor is installed at the front or rear of the vehicle to detect the guide line, and the steering angle of the vehicle is determined based on the way the sensor detects the guide line. It has been well known for a long time that this method is controlled.

FIGS. 3 and 4 schematically show a general configuration for guiding such an unmanned vehicle.

That is, in these Figures 3 and 4, 1 is the guide line laid on the track floor etc., 2 is the unmanned vehicle in question, and 3
a and 3b are the steering wheels of the unmanned vehicle 2, 4a and 4b
is also a fixed width, 10a and 10b are sensors for detecting the guide wire 1, and generally these sensors 10a and 1
The steering angles of the steered wheels 3a and 3b are controlled based on the comparison with the detection level of the guide line 1 obtained by 0b. Incidentally, FIG. 3 shows the general configuration of an unmanned vehicle 2 that travels forward along line 1, and FIG. 5 shows a general configuration of unmanned vehicle 2 that travels backwards along line 1. show. Further, in FIGS. 3 and 4, reference numeral 5 is provided near the sensors 10a and 10b, respectively, and wirelessly receives the induced current flowing through the induction wire 1, and
This is an inductive radio antenna used to perform necessary control based on the frequency, etc.

(Problems to be Solved by the Invention) Although this guidance method is still effective when the guide line 1 is laid in a straight line and the unmanned vehicle 2 is guided straight along it, When the guiding wire 1 is laid in a curved shape as shown in FIG. 4, the following inconvenience occurs during the guiding.

b) In such a guidance method, the steering angle command for the steered wheels 3a and 3b is generally the steering angle command=K・(right sensor (10b) output car left sensor (10a) output)・
...(1) Since K is given in the form of a constant, for example, the above sensor 1
When the guide line 1 faces the center of 0a and 10b, the steering angle command becomes "0". Therefore, when the 4th line 1 is curved, smooth control such as making the center of the sensor follow directly above the 4th line 1 is maintained whether the vehicle is traveling forward or backward as described above. Can not. This is due to the fact that although this guidance method can provide feedback on the displacement of the unmanned vehicle 2 from the guide line 1, it cannot provide any feedback on the declination angle, so that the unmanned vehicle 2 ends up meandering along the guide line 1. Only unstable guidance is possible, and if you try to maintain this guidance, the running speed will be extremely slow.

) Every time the unmanned vehicle 1i1 makes a turn along the guidance s1, the unmanned vehicle 1i1
Since there is a difference between the inner and outer wheels of i2, the width of this guide path needs to be made wide in consideration of these differences between the inner and outer wheels.

c) When using the above-mentioned guided radio antenna 5,
There is a difference in the optimal position for installation when the unmanned vehicle 2 is traveling forward and when it is traveling backwards. Therefore, countermeasures such as installing two antennas 5 or extending their length are required.

[Means and effects for solving the problem] In the present invention, for an unmanned vehicle traveling on the curved guide line, the displacements of at least three arbitrary points from the guide line are simultaneously measured. By detecting this, the arrangement curve of the four-wire line is approximated as a circle, and the radius of curvature and center of curvature are determined, and the center point of the vehicle, such as the center point of the fixed wheel, is determined based on the radius of curvature and center of curvature. The displacement of an arbitrary fourth point from the guiding line and the deviation angle of the vehicle's traveling direction from the guiding line arrangement direction centering on the fourth point are calculated at any time, and the calculated displacement and deviation angle are calculated as needed. The unmanned vehicle in question is steered so that the value becomes "0" or a predetermined value.

As a result, whether the unmanned vehicle is traveling forward or backward, it is possible to always guide the unmanned vehicle so that at least the fourth point is, for example, directly above the guide line.

[Effects of the Invention] As described above, according to the method of guiding a curved route for an unmanned vehicle according to the present invention, the center point of the curved path of the unmanned vehicle can be arbitrarily set, and the set center point of the vehicle can always be This can be placed in a desired fixed relationship to the guide line.

Therefore, the unmanned vehicle can be guided stably and at high speed even on such a curved route, and the trajectory will be exactly the same whether the vehicle is traveling forward or backward, especially if the center point of the vehicle is set at the center position of the fixed width. The width of the guide route itself can also be set narrower than in the past. Further, even when using the above-mentioned guided radio antenna, by installing the antenna at a position that is the center point of the vehicle, it is possible to ensure that the antenna follows the 4PJ.

[Example] Referring to FIG. 1, an example of the curved route guidance method for an unmanned vehicle according to this explanation will be described in detail.

Figure 1, like the previous Figures 3 and 4, is a plan view schematically showing the relative structure of the unmanned vehicle with respect to the guide line. In Figure 1, 1 is the guide line and 2 is the unmanned vehicle. 3a and 3b are steering wheels of the unmanned vehicle, 4a# and 4b are fixed wheels, 11a and 11b are first sensors for detecting guidance @1, 12a and '12b are second sensors, 13
Similarly, a and 13b respectively indicate the third sensor. In this embodiment, it is assumed that the three pairs of sensors are used to simultaneously detect the respective displacement amounts of arbitrary three points P, P2, and P3 of the unmanned vehicle 2 from the guide line 1. Hereinafter, the method of this embodiment will be described in detail, focusing on the manner of processing each detected displacement amount.

Now, as shown in the same ffT1 diagram, the fixed wheels 4a and 4
If the center position P4 of the uninhabited city @2 is set as the center point of the uninhabited city @2, and the y-axis and the y-axis are set around this point, the three points of interest P, , P2. The coordinates of P are (0, y), <o, for the set y-axis and y-axis, respectively.
y2 >, (o, !i'3 >, and similarly, the guide line 1 of these three points P1゜P, P
Coordinate point P1' above.

P2' and P' are (x, y,), respectively.

(x, y), (x, y).

Here, y,'/2. V3 is a value that is known in advance depending on the installation position of the three pairs of sensors in the unmanned vehicle 2, and X, X2, and X3 are the values of the three points of interest P1, which are detected by these three pairs of sensors, respectively.
P2. P3 induction I! This value corresponds to the amount of displacement from 1.

Further, as shown in the figure, the radius of curvature of the guide line 1 is r
and the coordinates of the center of curvature are (Xo.

yo), then the coordinates for the guide line 1 are (
x, y), (x X )2+(V V□)2=r −(2
) holds true. Here, the coordinates (x
, y) are at least (x , y
), (x, y >, (x, y3), so we first calculate these×1°X2.
X and! i', V2. By solving the 3'N simultaneous equations in which the values of '/3 are respectively substituted into
seek.

After obtaining the six values of r, x, and y in this way, we next calculate the displacement of the center point P4 (0, O) of the unmanned vehicle 2 from the guide line 1, that is, the coordinate point P'( x, O)
Find the value of x4 in . In other words, this is
This can be expressed as the value of X when y=0 is substituted into the above equation (2).

Next, using the thus obtained displacement of the vehicle center point P4 from the guide line 1 x 4 and the values of the above-determined curvature center coordinates (x, y) of the guide line 1, the vehicle center point P4 is determined. Find the angle of deviation of the vehicle's traveling direction from the guide line installation direction. The general idea is that the guidance line arrangement direction, that is, the guidance setting direction for the unmanned vehicle 2, is the tangential direction of the guidance line 1, so this is also adopted here.
As shown in FIG. 1, if the angle of deviation Δθ between the direction of travel of the vehicle and the tangential direction of line 1 is the desired angle of deviation of the vehicle, then this is Δθ=tan (yo / <xo −X4 )
) −(4).

After determining the displacement x4 and the deflection angle Δθ with respect to the guide line 1 with respect to the center point P4 of the vehicle 2 in this manner, in this embodiment, for example, the following calculation is performed to obtain the steering angle command value for the vehicle 2. That is, if this value is θi, θi=K (Kx−×4+θ・Δθ)−15) However, 1. Kx, θ: Constant If the steering angle command value θi is obtained in the form shown in equation (5), the vehicle 2 can be guided so that the displacement x 4 of the vehicle center and the deflection angle Δθ are both rOJ. If such a guidance is executed, the vehicle 2 will travel with the center of the vehicle always positioned directly above the guidance 4!1. Incidentally, in this embodiment, since the center of the vehicle is set at the center position of the fixed wheels 4a and 4b, the trajectory is exactly the same whether the vehicle is traveling forward or backward. Note that the constant in equation (5) above is 1°KX,
In this way, when guiding the unmanned vehicle 2, θ is preset as a meaningful value to make the steering system perform ideal steering control according to the actual situation of the vehicle. Desired weighting for the above-mentioned calculation elements x4 and Δθ, or their addition values, etc. can also be given.

As described above, in the guidance method of this embodiment, 1) the three pairs of sensors simultaneously detect the amount of displacement from the guide line 1 at any three points of the unmanned vehicle 2;

2) Calculating the radius of curvature and center of curvature of the corresponding traveling portion of the guide line 1 based on the simultaneous relationship of these three detected displacement amounts.

3) Calculate the displacement of an arbitrary point P4 (here, the center point of fixed wheels 4a and 4b) to be the center point of the unmanned vehicle 2 from the induction si based on the calculated radius of curvature and center of curvature.

4) Calculating the deviation angle of the direction of travel of the unmanned vehicle from the tangential direction of the guide line, centered on the center point P4, based on the calculated displacement and the center of curvature.

5) Steering the unmanned vehicle 2 so that the calculated displacement and deflection angle become "0".

The unmanned vehicle 2 is guided along the curved lure by continuously performing the following as the unmanned vehicle 2 travels, and this guidance method allows the unmanned vehicle 2 to be guided s1 as described above. It achieves stable running with reliable tracking.

In this embodiment, the center point of the unmanned vehicle 2 (desirably set at the center of the fixed wheels 4a and 4b as described above, but it is basically arbitrary and can be set freely depending on the actual situation of the vehicle). can be set) induce #! The case where the vehicle 2 is guided along directly above the guide line 1 has been shown, but as long as the displacement (×4) and the deflection angle (Δθ) of the vehicle 2 with respect to the guide line 1 are accurately obtained as described above. This guidance mode itself is arbitrary, and for example, the vehicle 2 may be guided while maintaining a certain distance from the guidance line 1, or in some cases, such distance may be adjusted as appropriate depending on the actual situation of the guidance route. It is also possible to guide the same vehicle 2 while changing the direction. This is the above displacement (×4)
This can be easily realized by simply changing the method of forming the steering command value (θi) based on the declination angle (Δθ) according to the actual situation.

Furthermore, the arrangement of each sensor is not limited to the example described above, but may be arbitrary, as long as the amount of displacement of the vehicle 2 from the guidance 111 can be obtained at at least three points.

In addition, although no particular mention was made of the induction method in the same embodiment, it may be a so-called electromagnetic induction method using induced current, or a white line tape or the like may be used as the guidance wire 1. A so-called optical guidance method in which reading is performed using an optical sensor may also be used. For example, this is M1
1 guidance method, and when using an inductive radio antenna as described above, by installing the antenna at the center point of the vehicle 2, it can be ensured that it follows the guidance Pi11. can be done.

Finally, an example of a guidance device that is mounted on the unmanned vehicle 2 and implements this guidance method will be described with reference to FIG. 2.

In the device shown in FIG. 2, the first sensor 11, the second
The sensor 12 and the third sensor 13 are the three pairs of sensors 1 described above.
1a and 11b, 12a and 12b, 13a and 13b (Fig. 1), and their respective guiding wire detection signals are processed as desired by signal processing circuits 21, 22, and 23 to obtain the three points of interest mentioned above. P, P2. P3 guide line 1
Obtain values corresponding to the respective displacement amounts X 1 , X 2 , and X 3 from . These displacements fJx, X2, and X3 are taken into the first computing unit 30 all at once.

The first computing unit 30 calculates the above (3 ), solve the simultaneous equations shown in equation 1, and calculate the radius of curvature r of guide line 1 and its center coordinate of curvature (x
.

The second arithmetic unit 40 calculates the added r and (x, y
) is used to calculate the equation (2) of the previous O under the condition of y=0, and calculates the displacement x4 of the center point of the unmanned vehicle 2 from the guide line 1. . The value of displacement x 4 thus obtained is added to the next third computing unit 50, and is also given to the steering angle command value computing unit 60 as displacement information which is one of the steering angle command value computing elements.

The third arithmetic unit 50 calculates the value of x4 added above and the first
The coordinates of the center of curvature of the di'4 line 1 obtained by the calculator 30, that is, X and y. This is a computing unit that calculates the deviation angle Δθ of the direction of travel of the unmanned vehicle from the direction in which the guide line is disposed, centered on the vehicle center point, by executing the calculation of the above equation (4) using the value of . The value of the yaw angle Δθ thus obtained is also given to the steering angle command value calculator 60 as yaw angle information, which is another element of the steering angle command value calculation element in the present invention.

The steering angle command value calculator 60 calculates the displacement information 4, the argument information Δθ, and the constants Ki and K which are appropriately preset.
This is a calculation unit that calculates the value of θi in the opening equation by executing the calculation of equation (5) using θ in x, and the value of θi thus obtained is the steering angle for the vehicle 2 at each time. The command value is given to the automatic steering system 70 of the vehicle 2.

The automatic steering system 70 is a well-known control circuit consisting of an adder 71, a driver 72, an actuator 73, a steering mechanism 74, and a steering angle sensor 75. As shown in FIG. While feeding back the detected value of θt to the adder 71, the steering angles of the steered wheels 3a and 3b (see FIG. 1) are adjusted so that the difference between the command value θi given above and this large steering angle θt becomes "0". Control.

Note that the first to third computing units 30 to 50 and the steering angle command value computing unit 60 may be collectively configured by a microcomputer or the like.

[Brief explanation of drawings]

FIG. 1 is a plan view schematically showing the relative structure of a guide line and an unmanned vehicle in an embodiment of the curved route guidance method for an unmanned vehicle according to the present invention, and FIG. 2 is a plan view schematically showing the relative structure of the guide line and the unmanned vehicle. A block diagram showing an example of a guidance device, and FIGS. 3 and 4 are plan views each schematically showing the relative structure of a guidance line and an unmanned vehicle in a conventional guidance method. 1... Guide line, 2... Unmanned vehicle, 3a, 3b...
Steering wheels, 4 a r 4 b”/fixed wheels, 10a, 1
0b, 11a, 11b, 12a, 12b, 13a, 13
b...Sensor. KuZ-2J

Claims (1)

[Claims] A curved route guidance method for an unmanned vehicle that guides an unmanned vehicle along a guide line arranged in a curve, the method comprising: simultaneously detecting the amount of displacement of at least three arbitrary points of the unmanned vehicle from the guide line; Calculating the displacement of an arbitrary fourth point, which is the center point of the unmanned vehicle, from the guide line and the deviation angle of the direction of movement of the unmanned vehicle from the guide line arrangement direction with the fourth point as the center; A curved route guidance method for an unmanned vehicle, comprising steering the unmanned vehicle so that the calculated displacement and deflection angle become "0" or a predetermined value.