JPS5965316A - Guiding method of unmanned truck - Google Patents

Abstract

PURPOSE:To increase the position detecting accuracy and to facilitate an easy change of route, by storing previously the information on a distance between the truck body and an object at the side of a traveling route and comparing this information with an actually measured distance to perform the steering control. CONSTITUTION:A controller 1 using a microcomputer, etc. is set on an unmanned truck which travels automatically between working points within a plant. A storage part 1a of the controller 1 stores the information on a distance between a reference line l0 and the left/right wall surfaces for each unit distance (L1-R1, L2-R2-) of the traveling direction of the truck. In addition, the truck contains distance measuring meters 2l and 2r to measure the distances to the left and right wall surfaces. These measured values are read into a comparator 1b in a proper cycle. Then these measured values of the comparator 1b are compared with said stored distance information. The steering compensating signals are supplied to driving circuits 5l and 5r in order to eliminate the deviation produced from the comparison. These compensating signals are superposed on the speed signal and supplied to driving servo motors 4l and 4r for left and right wheels. Thus an unmanned truck is controlled for its traveling.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of guiding an automatic guided vehicle, and particularly an object of the present invention is to provide a method of guiding an automatic guided vehicle that allows the automatic guided vehicle to autonomously and appropriately travel without providing guidance information from the outside.

The guiding method for automatic guided vehicles that automatically travel between work points, transfer points, and waiting points in a factory is to run current through wires buried under the floor and follow the resulting electromagnetic waves; There is a known method in which a light-reflecting tape attached to the surface follows the surface, but in the former method, the burying work is a painstaking process;
It has the disadvantage that it is not easy to change the running route, and it is necessary to constantly pass current through the wire. The latter allows for easy route changes, but has drawbacks such as being trampled by forklifts or other vehicles or people and getting dirty, which impedes stable running due to a decrease in reflectance.

The present invention has been made in view of the above circumstances, and aims to provide a method for guiding an automatic guided vehicle that does not require ground equipment such as under-floor wires and can change routes only by changing software. purpose.

The automatic guided vehicle guidance method according to the present invention provides information on the distance between the vehicle body and an object existing on the side of the traveling route in advance in association with the position in the traveling direction, and actually measures the distance while traveling, It is characterized by performing steering control to eliminate the difference between the measured distance and distance information given in advance.

The method of the present invention will be specifically explained below based on the drawings.

FIG. 1 is a diagram for explaining the principle of the method of the present invention. Dot-dashed line l. indicates the reference line of the travel route, and on the left and right sides there are loads such as walls, machines, partition plates, materials, work in progress, products, etc. (all shown with hunting), and the conveyance is carried out through the gaps between these. It is used as a vehicle passage.

The transport vehicle has a control device 1 using a microcomputer, etc.
The storage unit 11 stores distance information from the reference line 10 to the left and right walls (hereinafter referred to as walls) for each unit distance d in the running direction (LO, RO), (L+
, Rt ), (Ll1 R2) −(Li, Ri)
-(Ln-+, Rn-t), (Ln, Rn).

On the other hand, the transport vehicle is provided with distance meters 21 and 2r for measuring the distance to the left and right walls, and the measured values are read into the comparator 1b in the control circuit 1 at appropriate intervals. In addition, a rotary encoder 3 for detecting travel distance is provided in the part that is linked to the wheels of the conveyor/transfer vehicle (it may be provided on each of the left and right wheels, or one may be provided on the center trailing wheel, etc.), and the rotation of the wheel. A number of pulses corresponding to the amount are emitted, and the pulses are input to a counter 1c in the control circuit 1. The counter 1c emits a pulse every number corresponding to the traveling distance d, and provides this to the address counter 1d of the storage section 1a. The control circuit 1 sequentially reads out the stored information in the storage section 1a according to the contents of the address counter 1d and supplies it to the comparator 1b.

The comparator 1b compares the actually measured distance on the left and right sides with the distance information on the left and right sides read out from the storage unit 1a. If the deviation of the comparison data exceeds a predetermined value, the control circuit 1 controls the servo motors 41 + 4 r provided for driving the left and right wheels, respectively.
The drive circuit 57? , 5r to issue a steering correction signal to eliminate the deviation. The drive circuit 5 l + 5 r is a servo motor 4 f so as to realize the speed signal constantly given from the control circuit 1 .

It is composed of a servo circuit etc. that controls the rotation of 4R,
The steering correction signal is given so as to be superimposed on the speed signal. Of course, the distance information given from the storage section 1a to the comparator 1b is updated each time the vehicle travels the distance d.

In the above example, the rotary encoder 3 is used to detect the traveling distance or the position in the traveling direction, and the distance information used as a comparison standard is read and updated accordingly, but the uneven pattern on the wall surface is clear. Or the steering control system has good responsiveness, which is standard A7? If conditions such as the vehicle does not deviate significantly from a or the travel speed is slow are met, it is also possible to update the comparison reference distance information based on the actual measurement data of the range finder. Figure 2 is an explanatory diagram of this, where the road width between Y1 and Y2 is w, and the road width between y2 and Y3 is W2.
So, W2 W! =ΔR1. In this case as well, the content given to the storage unit 1a as distance information is the reference line l. This is the distance between the left and right walls and the level difference of unevenness such as ΔR1, but for the range of Y1 to Y2 (L
l, R□)...However, + R, = W1, Y2 ~ Y
For the range of 3 (L2.R2)...However, L2+R2
=W2 only. The actual measured distance data of the rangefinder 21+2r is read into the comparator 1b at regular intervals, and compared with the read information from the storage section 1a, the drive circuit 5 is operated to eliminate the deviation.
j! ', 5r is emitted as before, but the difference is that the information read from the storage section 1a is updated as follows.

That is, the CPU of the control circuit 1 controls the rangefinder 2 as shown in FIG.
1! , 2r, the data Lm, Rm and t, ,
m Lm-'+ 'R=Rm Rm-1'F
: If the ratio value at TX is within the allowable range α, it is assumed that there is no change in the travel path width or wall surface, and the read address of the storage unit 1a is not changed. On the other hand, if one side exceeds α, the step information in the storage unit 1a (ΔR on the right side)
Further judgment processing is performed based on the presence of a level difference of 1. In other words, in this case, the magnitudes of ΔL and α, Δπ, and ΔR1±α are compared, and 1Δ[1≦α, ΔR1−α≦1Δn1
If ≦ΔR1+α, it is assumed that the step has been passed and the read address is updated, and the previous (L,,R,)
The comparison is changed from the comparison with (L2.R2) to the comparison with (L2.R2).

If the above conditions are not met, the read address is retained as it is.

By using such a method, the self-propelled vehicle can update the distance information to the wall surface on which the vehicle is traveling.

Note that this type of automated guided vehicle may be equipped with a function to recognize its own position, but it is possible to have the recognized position corrected when a step is detected as described above. , the accumulation of errors can be avoided.

Now, in terms of steering control, the reference line l. It is necessary to consider the positional deviation from the starting point and the deviation in the direction of movement. Of course, the former can be easily obtained as the difference between LL Ri in the storage section and the actual measurement value Li+Ri. On the other hand, the latter can be found as follows. That is, as shown in FIG. 4, the tread of the transport vehicle is Tr, the actual value measured by the distance meter 21.2r is L"i, π11, and the short distance information in the storage section la at this portion is Li, I.

Then, the reference line l. The deviation θi in the traveling direction from the vehicle is determined based on the triangle ABC in the figure as Li+Ri Oi = cos-' -1-7-- Li + Ri + Tr, and steering control is performed based on this.

Note that when θi becomes larger than a certain level, the comparison between the actual measurement value and the stored distance information becomes meaningless. This is because the former is larger than the latter on both the left and right sides. Therefore, when θi becomes larger than a predetermined value, the storage distance information LL Ri is corrected to Li cosecθL Ri cosecθi, and then compared with the actual measurement value C1, πi to detect the deviation from the reference line lo. Correction is required.

In the case of the present invention as described above, no special ground equipment is required, and the conveyance vehicle can be run as is on a general path defined by a wall. The route can be changed by simply rewriting the distance information in the software, that is, in the storage unit. ,
Furthermore, since the distance to the wall is measured and this is used as guidance information, the narrower the passage, the higher the accuracy. Furthermore, the more uneven the wall surface of this passage is, the more information about the traveling direction is obtained, and the more accurate the position detection in that direction is, the more the present invention exhibits excellent effects.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are drawings together showing an explanatory diagram of the principle of the method of the present invention and a block diagram showing an apparatus for carrying out the method;
FIG. 3 is a 70-chart of the read address updating process, and FIG. 4 is an explanatory diagram of the algorithm for calculating the shift in the advancing direction. 1... Control circuit 1a... Storage section 21, 2r.-
・Distance meter 3...Rotary encoder 41+ 4r...
・Servo motor 5f, 5r... Drive circuit Fig. 1 Fig. 2 Fig. 3 Fig. %4 Fig.

Claims (1)

[Claims] 1. Information on the distance between the vehicle body and an object existing on the side of the driving route is given in advance in relation to the position in the driving direction, and the distance is actually measured while driving, and the measured distance and the distance information given in advance are calculated. A method for guiding an automated guided vehicle, characterized by controlling steering to eliminate the difference between the two.