Method and apparatus for interlocking entrance of unmanned dump truck into work area

The present invention is a method and an apparatus for preventing the entrance of an unmanned dump truck, so that an interference and a collision between the unmanned dump trucks and a working vehicle in the working area are prevented. In the method, an unmanned dump truck (3) enters the working area (91) only when another dump truck (3a) is not in the working area (91) and the working vehicle (92) in the working area (91) issues an entrance permission command. The apparatus includes entrance permission means (22), provided on the working vehicle (92), and computing means (11), for outputting a control command thus permitting the unmanned dump truck (3) to enter only when another dump truck (3a) is not in the working area (91) and an entrance permission command is inputted into the apparatus.

TECHNICAL FIELD 
The present invention relates to a method and an apparatus for preventing 
the entrance of an unmanned dump truck into a work area, so that 
interference and collision between vehicles are prevented, and the 
invention particularly relates to a method and an apparatus for preventing 
the entrance of an unmanned dump truck when the unmanned dump truck enters 
the inside of a loading area where a loader works. 
BACKGROUND ART 
Conventionally, an unmanned dump truck driving system is well known as a 
system for transporting earth and sand by a dump truck in a wide range of 
quarries or the like. The examples of the aforementioned unmanned dump 
truck driving system are as described below. Teaching a traveling course 
of an unmanned dump truck has been previously conducted by a specified 
method, and the coordinate data at each predetermined distance on the 
traveling course, or at predetermined times, are stored in a storage 
device. During automatic traveling, the unmanned dump truck confirms the 
current position at each predetermined sampling time, and the deviation 
between the actual traveling position and the aforementioned traveling 
course data, as previously stored, is computed. The steering, vehicle 
speed, and starting and stopping of the unmanned dump truck are controlled 
to decrease the deviation, so that the unmanned dump truck is controlled 
to travel along the traveling course previously stored. 
Normally, at specified positions in an unmanned dump truck driving system, 
a loading site is provided, in an excavating and quarrying site (commonly 
called a face, and hereinafter referred to as a face), where earth and 
sand or the like are loaded into the rear deck of the unmanned dump truck, 
and an earth discharging site (commonly called a hopper, and hereinafter 
referred to as a hopper) is provided where earth and sand or the like, 
which have been loaded, are discharged. A plurality of unmanned dump 
trucks travel between the loading site and the hopper along an automatic 
traveling course, and repeatedly conduct the operation of discharging the 
earth and sand or the like, which have been loaded by a loader at the 
loading site, into the hopper. In such an unmanned dump truck driving 
system, in many cases, a plurality of unmanned dump trucks are traveling 
in close proximity to one another in a working area, for example, a 
loading site, and it is important to prevent collision between these 
unmanned vehicles. 
As a method relating to the prevention of collision, a method for 
controlling the traveling of an unmanned motor vehicle, such as an 
unmanned dump truck, is disclosed in, for example, Japanese Laid-open 
Patent Application No. 5127746. FIG. 5 shows a traveling control method, 
in a loading area 91 around a face, where a loader (working vehicle) 92 
works. The unmanned dump truck 3 has position detecting means (not 
illustrated) for detecting its current position in a coordinate system on 
an automatic traveling course 96. The unmanned dump truck 3 travels 
automatically, with the speed, steering, and the like being controlled by 
a control means (not illustrated), so as to decrease the deviation 
obtained by comparing the course data, previously determined by teaching 
or the like, to the current position detected by the position detecting 
means. In one embodiment, a plurality of unmanned dump trucks 3, 3a, and 
3b are traveling on the same automatic traveling course 96. The unmanned 
dump truck 3 transmits its current position to other unmanned dump trucks 
3a and 3b by means of a transmitter (not illustrated), and receives the 
current positions of the other unmanned dump trucks 3a and 3b by means of 
a receiver (not illustrated), so that they recognize the positions of each 
other. 
At the face, the loader 92 loads the unmanned dump truck 3a at a 
predetermined position. FIG. 5 shows a situation in which the unmanned 
dump truck 3a stops at a loading position 2. At this point, it is assumed 
that the other unmanned dump trucks 3 and 3b are approaching the loading 
position 2, traveling on the automatic traveling course 96a, leading to 
the face from the hopper. The control means of the unmanned dump truck 3 
inputs the current position of the unmanned dump truck 3a by means of the 
receiver, and when it is determined that the unmanned dump truck 3a is in 
the loading area 91, the control means halts the unmanned dump truck 3 at 
a standby point 94 provided just before the entrance of the loading area 
91 on the automatic traveling course 96a. When the preceding unmanned dump 
truck 3a runs along a loading course 96c, leading to the hopper, after 
completion of loading, and enters the inside of a designated area 95, 
provided on an automatic traveling course 96d, leading to the hopper, the 
unmanned dump truck 3, at the standby point 94, starts and travels along 
an automatic traveling course 96b into the loading area 91. 
When the unmanned dump truck 3 at the standby point 94, judges that the 
preceding unmanned dump truck 3a has left the loading area 91 and is 
traveling on the automatic traveling course 96d, it starts from the 
standby point 94 and enters the inside of the loading area 91. Thereafter, 
the unmanned dump truck 3 reverses from the automatic traveling course 96b 
and stops at the loading position 2. As described above, interference and 
collision among the unmanned dump trucks 3, 3a, and 3b, in the loading 
area 91 are prevented. 
Normally, after the loading operation, the loader 92 in the loading area 91 
cleans up spilled earth and sand and makes preparations for the next 
loading at the loading position 2. It the next unmanned dump truck 3 
enters the inside of the loading area 91 during the aforementioned 
operations, there is a danger that an interference or a collision between 
the unmanned dump truck 3 and the loader 92 may occur. 
However, according to the aforementioned conventional method for preventing 
the entrance into a working area by traveling control, the next unmanned 
dump truck 3 enters the inside of the loading area 91 even when the loader 
92 has not completed the preparations for loading. Accordingly, the 
operator of the loader 92 has to conduct preparing operation while 
confirming the position of the unmanned dump truck 3, which is advancing 
thereto. For this reason, the disadvantages of decreased operation 
efficiency of the loader 92, increased fatigue of an operator under 
excessive mental load, and greater risk of interference and collision with 
the unmanned dump truck 3 arise. 
SUMMARY OF THE INVENTION 
The present invention is made to eliminate the aforementioned disadvantages 
of the conventional art, and its object is to provide a method and an 
apparatus for preventing the entrance of an unmanned dump truck into a 
working area, so that an interference and a collision between unmanned 
dump trucks, or between a working vehicle and the unmanned dump trucks, 
are prevented. 
A method and an apparatus for preventing the entrance of an unmanned dump 
truck into a working area, according to the present invention, include 
setting and storing an automatic traveling course of an unmanned dump 
truck; a working area which includes part of the automatic traveling 
course, and in which a working vehicle works; a standby point located on 
the automatic traveling course and just before the working area, wherein 
the unmanned dump truck transmits and receives position coordinate data to 
and from another unmanned dump truck during automatic traveling on the 
automatic traveling course; traveling on the automatic traveling course 
after confirming the position of each other; entering the inside of the 
working area, or waiting at the standby point; having a characteristic in 
that during automatic traveling, the unmanned dump truck enters the inside 
of the working area only when another unmanned dump truck is not in the 
working area and the working vehicle inside the working area issues an 
entrance permission command. 
According to the aforementioned embodiment, when the unmanned dump truck is 
to enter a specified working area within the automatic traveling course, 
the unmanned dump truck can enter the working area only when another 
unmanned dump truck is not in the working area and the working vehicle in 
the working area (for example, loader or the like) issues an entrance 
permission command. If either of the aforementioned two conditions is not 
satisfied, specifically, if another unmanned dump truck is in the working 
area, or if an entrance permission command is not issued, the unmanned 
dump truck is halted at the standby point, which is provided just before 
the aforementioned working area, until these two conditions are satisfied. 
Therefore an interference and a collision between the unmanned dump 
trucks, or between the unmanned dump trucks and the working vehicle, are 
prevented. Therefore, operability of the working vehicle in the working 
area is improved, and the working load on the operator of the working 
vehicle can be reduced. 
Further, in the aforementioned configuration, on setting the automatic 
traveling course, a round course return point may be set on the return 
way, where the unmanned dump truck heads for another working area from the 
present working area in a lateral direction from the standby point, 
wherein the working area may include the automatic traveling course from 
the standby point up to the round trip return point. 
According to the aforementioned embodiment, the round trip return point is 
located on the aforementioned return way in a lateral direction from the 
standby point, therefore it can be automatically set. Accordingly, the 
part of the automatic traveling course, which is included in the working 
area, can be easily set, and a precise and safe working area can be set. 
As for the position "on the return way in a lateral direction from the 
standby point", a point on the return way at a shortest distance from the 
standby point, or a point on the return way, at a predetermined distance 
away from the standby point at a shortest distance from the standby point, 
is desirable. 
An apparatus for preventing the entrance of an unmanned dump truck into a 
working area, according to the present invention, is an apparatus in which 
an unmanned dump truck includes position detecting means for detecting the 
position of the unmanned dump truck traveling on an automatic traveling 
course, part of which is included in a working area for a working vehicle; 
computing means for comparing the data of the aforementioned detected 
position to the position data previously stored and outputting commands to 
control the unmanned dump truck; traveling control means for controlling 
the unmanned dump truck based on the control commands; and a 
transmitter/receiver for transmitting the aforementioned position data, 
which are detected based on a command from the computing means, and for 
receiving the position data of another unmanned dump truck. The traveling 
control means allows the unmanned dump truck to enter the inside of the 
working area when another unmanned dump truck is not in the working area, 
wherein the working vehicle in the working area has an entrance permission 
means. The computing means outputs a control command to the traveling 
control means to allow the unmanned dump truck to enter the working area 
only when another unmanned dump truck is not in the working area and the 
entrance permission command for the unmanned dump truck is provided by the 
entrance permission means. 
According to the aforementioned configuration, the unmanned dump truck 
enters the working area only when another unmanned dump truck is not in 
the working area and the entrance permission command is provided, 
therefore an interference and a collision in the working area can be 
prevented, operability of the working vehicle can be improved, and the 
load on the operator of the working vehicle can be reduced, as in the 
aforementioned method of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION 
A preferred embodiment of the present invention will be described in detail 
below with reference to the attached drawings. In the present embodiment, 
as FIG. 2 illustrates, a loader 92 is shown as an example of a working 
vehicle, and a loading area 91 where the loader 92 works is an example of 
a working area for the working vehicle. 
FIG. 1 illustrates a block diagram of an embodiment of an unmanned dump 
truck 3 and the loader 92. A computing means 11, of the unmanned dump 
truck 3, controls the entire automatic traveling, and can be primarily 
composed of an ordinary computer system, for example, a micro computer. A 
position detecting means 12 detects the position of the unmanned dump 
truck 3, in a coordinate system, on an automatic traveling course, and 
outputs the position data to the computing means 11. In the position 
detecting means 12, there are means for detecting an absolute coordinate 
position, by a GPS system or the like, and means for obtaining a relative 
coordinate position, from a known reference position, by computation, 
based on traveling direction data detected by a gyro or the like, and 
traveled distance data detected from the rotational frequency of wheels or 
the like. A traveling control means 14 controls the steering, vehicle 
speed, braking, and the like, of the unmanned dump truck 3, based on a 
command from the computing means 11. Specifically, the traveling control 
means 14 conducts, for example, steering control by a steering control 
motor, vehicle speed control by a transmission control valve and an 
acceleration control valve, braking control by a brake cylinder control 
valve, and the like. 
Further, a memory means 15 stores coordinate data for an automatic 
traveling course 96 (see FIG. 2) at predetermined times, which are 
previously set by teaching or the like. During automatic traveling, the 
computing means 11 outputs a command to the traveling control means 14 to 
decrease the deviation between the stored coordinate data and the position 
data detected by the position detecting means 12. Thereby the traveling 
control means 14 controls traveling by controlling the steering, vehicle 
speed, braking and the like of the unmanned dump truck 3. A 
transmitter/receiver 13, of the unmanned dump truck 3 transmits the 
position data of the unmanned dump truck 3 to another unmanned dump truck 
3a, which is inputted from the computing means 11 (see FIG. 2). The 
transmitter/receiver 13 receives the position data of the unmanned dump 
truck 3a from the unmanned dump truck 3a, and outputs the same data to the 
computing means 11. The transmitter/receiver 13 further receives an 
entrance permission command from the loader 92. The position coordinate 
data and each command may be transmitted or received by the 
transmitter/receiver 13 via a monitoring station 30, provided at a 
predetermined position within the unmanned dump truck driving system, or 
they may be directly transmitted or received without being relayed to the 
monitoring station 30. 
In the loader 92, a computing means 21 controls the transmission to and 
reception from the unmanned dump truck 3, and is composed of an ordinary 
computer system similar to the computing means 11 of the unmanned dump 
truck 3. The computing means 21 transmits and receives command signals and 
position data to and from the computing means 11 via the 
transmitter/receiver 23 of the loader 92 and the transmitter/receiver 13 
of the unmanned dump truck 3. An entrance permission switch (entrance 
permission means) 22 is a switch for the driver of the loader 92 to permit 
the entrance of the unmanned dump truck 3 into the loading area 91 (see 
FIG. 2). The computing means 21 inputs an actuating signal from the 
entrance permission switch 22, and transmits the entrance permission 
signal via the transmitter/receiver 23 when the actuating signal is set to 
"On". A standby vehicle indicator 24 indicates that the unmanned dump 
truck 3 is on standby at a standby point 94 (see FIG. 2) just before the 
loading area 91. The computing means 21 produces a decision based on the 
position data of each of the unmanned dump trucks 3 and 3a, which is 
received therein, and indicates that the unmanned dump truck 3 is on 
standby with the standby vehicle indicator 24, when the unmanned dump 
truck 3 is at the standby point 94. The indication may be given, for 
example, by using a lamp, or by showing a message on a graphic display 
device, such as a CRT. 
FIG. 2 is an example of the automatic traveling course 96, wherein a 
plurality of unmanned dump trucks 3 and 3a are automatic traveling along 
the automatic traveling course 96 between a loading site 2 and an earth 
discharging site (another working area) 1. FIG. 2 shows a situation with 
two unmanned dump trucks 3 and 3a to simplify the explanation, but the 
same explanation is applicable for a situation with three or more unmanned 
dump trucks. The loader 92 works in the vicinity of the loading position 2 
at the face, wherein the working area of the loader 92 is designated as 
the loading area 91. The standby point 94 is provided at a position just 
before the loading position 2, on the way along the automatic traveling 
course 96, leading to the loading position 2 from the earth discharging 
site 1. A round trip return point 97 is provided on the automatic 
traveling course 96, leading to the earth discharging site 1, from the 
loading position 2. The round trip return point 97 corresponds to an exit 
point from the loading area (working area) 91. In this embodiment, the 
area, which is in the vicinity of the automatic traveling course 96, from 
the standby point 94, via the loading position 2, to the round trip return 
point 97, is called the loading area 91. 
The location of the standby point 94 is set during teaching, and a 
predetermined halting position is stored as the standby point 94 on the 
course, wherein forward movement is taught from the earth discharging site 
1 to the loading position 2. The location of the round trip return point 
97 may be obtained by computation, for example, as the position which is 
on the return way of the automatic traveling course 96, leading to the 
earth discharging site 1, from the loading position 2, and which is in a 
lateral direction from the standby point 94 (in FIG. 2, directly above the 
standby point 94). Specifically, after calculating the distance between 
each point on the automatic traveling course 96, from the loading position 
2 to the discharging site 1 and the standby point 94, the point having the 
shortest distance from the standby point 94 may be the round trip return 
point 97. The location of the round trip return point 97 may be also a 
point on the return way at a predetermined distance from the standby point 
having the shortest distance from the standby point 94. The present 
embodiment has a method in which the loading area 91 is set during 
teaching as described above, but it is not restricted to this method. It 
is suitable to apply other methods, for example, in which the total 
teaching course data are read into an editing device (a personal computer 
or the like), which is installed in a predetermined place, after the 
completion of teaching, by writing the data to an IC card or the like, or 
by using data communications, in which the loading area 91 on the course 
data is designated by means of the course data edit function of the 
personal computer. 
Next, based on the flow chart in FIG. 3, the operation of the present 
embodiment is explained with reference to FIGS. 1 and 2. FIG. 3 shows a 
method for preventing the entrance of the unmanned dump truck 3 into the 
loading area 91. It should be noted that each step number is shown with a 
preceding "S", for example, "Step 1" is shown as "S1" in the following 
flow chart. 
S1: After leaving the earth discharging site 1, the computing means 11 of 
the unmanned dump truck 3 compares the current position data, detected by 
the position detecting means 12 to the course data, previously stored in 
the memory means 15, and outputs steering and vehicle speed commands to 
the traveling control means 14, so as to decrease the deviation between 
the above data. Thus, the unmanned dump truck 3 heads for the loading area 
91, from the earth discharging site 1, along the automatic traveling 
course 96. At the same time, the current position data of the unmanned 
dump truck 3 is transmitted to another unmanned dump truck 3a, or the 
like, and the loader 92, via the transmitter/receiver 13. When the 
unmanned dump truck 3 approaches the standby point 94, just before the 
position where the unmanned dump truck 3 enters the loading area 91, the 
computing means 11 outputs a braking command to the traveling control 
means 14 to decelerate the unmanned dump truck 3, and halts the dump truck 
3 when it reaches the standby point 94. 
S2: The computing means 11 receives the position data of another unmanned 
dump truck 3a, or the like, by means of the transmitter/receiver 13, and 
determines whether another dump truck 3a, or the like, is inside the 
loading area 91. When another unmanned dump truck 3a, or the like, is 
therein, control is returned to the beginning of S2 to wait until the dump 
truck 3a, or the like, leaves the loading area 91. When the dump truck 3a, 
or the like, is not therein, a command is given to proceed to S3. 
S3: The computing means 11 determines whether an entrance permission 
command has been received from the loader 92 via the 
transmitters/receivers 23 and 13. When the permission command is not 
received, control is returned to the beginning of S3 to wait until the 
entrance permission command is received. When the permission command is 
received, a command is given to proceed to S4. The entrance permission 
command is transmitted by the driver of the loader 92. Specifically, 
before transmitting the entrance permission command, the operator of the 
loader 92 confirms the completion of the preparations for the next loading 
operation and checks whether the unmanned dump truck 3 on standby is at 
the standby point 94, by looking at the standby vehicle indicator 24. When 
the unmanned dump truck 3 is at the standby point, the driver of the 
loader 92 manipulates the entrance permission switch 22. The computing 
means 21 then transmits the entrance permission command from the 
transmitter/receiver 23 and permits the entrance of the next unmanned dump 
truck 3 into the loading area 91. 
S4: The computing means 11 outputs a starting command to the traveling 
control means 14 and allows the unmanned dump truck 3 to enter the inside 
of the loading area 91. The computing means 11 allows the unmanned dump 
truck 3 to travel along the automatic traveling course 96 until it reaches 
the loading position 2, where the computing means 11 stops the unmanned 
dump truck 3 by issuing a braking command. 
Thus, an interference and a collision between the unmanned dump trucks 3 
and 3a, or the unmanned dump trucks 3 and 3a and the loader 92, in the 
loading area 91, can be prevented, and the traveling safety of the 
unmanned dump trucks 3 and 3a is improved. It should be noted that the 
present invention is not limited to an application in a loading area 91, 
but is applicable to any situation wherein interference between vehicles 
is prevented in working areas, for example, at an earth discharging site 1 
and the like. 
In the aforementioned embodiment, the computing means 11, which controls 
the entire automatic traveling of the unmanned dump trucks 3 and 3a, based 
on the position data of the unmanned dump trucks 3 and 3a and the entrance 
permission command, is located in the unmanned dump trucks 3 and 3a, but 
the location is not limited to the above. For example, as illustrated in 
FIG. 4, a computing means 25 may be disposed in a manned ground monitoring 
station 30A, provided in the unmanned dump truck driving system, or in the 
loader 92. In this embodiment, the computing means 25 comprises the 
computing means 21, to which the aforementioned entire automatic traveling 
control function of the computing means 11 is added. The ground monitoring 
station 30A or the loader 92 includes the transmitter/receiver 23; the 
entrance permission switch 22, which is manipulated by an operator; and 
the standby vehicle indicator 24, as well as the memory means 15, for 
storing the course data of the automatic traveling course 96. Meanwhile, 
the unmanned dump trucks 3 and 3a have computing means 11a, without the 
aforementioned entire automatic traveling control function, instead of the 
computing means 11 shown in FIG. 1, and omits the memory means 15 in FIG. 
1. 
In the aforementioned embodiment, the computing means 25 outputs a command 
to the traveling control means 14, via the transmitters/receivers 23 and 
13 and the computing means 11a, so as to decrease the deviation between 
the course data stored in the memory means 15 and the position data 
detected by the position detecting means 12. When the unmanned dump truck 
3, on standby, is at the standby point 94, and if the entrance permission 
command, notifying that another unmanned dump truck 3a is not inside the 
loading area 91, is outputted from the entrance permission switch 22, the 
computing means 25 issues a starting command to the traveling control 
means 14 of the unmanned dump truck 3, via the transmitters/receivers 23 
and 13 and the computing means 11a, and allows the unmanned dump truck 3 
to enter the loading area 91. 
INDUSTRIAL APPLICABILITY 
The present invention is useful as a method and an apparatus for preventing 
the entrance of an unmanned dump truck into a working area, so that an 
interference and a collision between unmanned dump trucks, or between a 
working vehicle and unmanned dump trucks, can be prevented.