In the wide-area working site of quarries, mines, and the like, in performing an earth and sand transportation work, it is required to intend avoidance of an accident due to the fatigue of a worker driving an off-road dump truck, manpower saving, and improvement of the productivity by prolonging the working time. Then, instead of using a manned vehicle, for example, a manned off-road dump truck, an unmanned vehicle drive system for operating an unmanned off-road dump truck has been introduced. Off-road dump trucks include that which uses a diesel engine as a power source to drive the wheels for traveling, and that which drives the diesel engine to operate a power generator, and uses the generated electric power to drive an electric motor for transmitting the driving force of the electric motor to the wheels for traveling.
The working site where an off-road dump truck(s) travels has particular areas, such as a loading site, and an earth removing site. These particular areas are mutually jointed by a maintained transportation road, called a haul road, sidetracks extending from the haul road to the particular areas, called access roads, and junctions.
The loading site, which is one of the areas, is a site where earth and sand are loaded onto an off-road dump truck (in the present invention, to be referred to as an unmanned vehicle), and in this site, an excavation work and an operation of loading a load, such as earth and sand, and the like, onto the unmanned vehicle are performed, using a working vehicle (in the present invention, to be referred to as a loading machine), such as a shovel (for example, a hydraulic excavator), a backhoe, and a wheel loader.
(Single-Side Loading)
FIG. 12 illustrates a case where single-side loading is performed in a loading site 1. As shown in the same FIG. 12, the single-side loading is a loading operation in which there is generated a travel route 10 for causing an unmanned vehicle 20 to travel from an entrance point 11 of the loading site 1 to a loading point 12, where a loading machine 30 exists, and the unmanned vehicle 20 is traveled under travel control along the generated travel route 10, and at the loading point 12, is loaded with a load by the loading machine 30. In other words, the single-side loading is a loading operation in which the unmanned vehicle 20 is caused to travel to a single side of either left or right side with respect to the loading machine 30, and is stopped at the loading point 12 during the loading operation. Herein, the travel route 10 includes a path from the entrance point 11 to a waiting point 14, and a final approach 16, which is a path from the waiting point 14 to the loading point 12. The path from the loading point 12 to an exit point 15 is referred to as an exit route 17 (17L, 17R).
The loading machine 30 is, for example, a hydraulic excavator, having a base carrier 30A with a crawler, and an upper slewing structure 30B which is slewable leftward and rightward. To the upper slewing structure 30B, a working machine 30C equipped with a boom, arm, and bucket is connected, and by operating the working machine 30C, the earth and sand, and the like, are scooped up for making an operation of loading them onto the unmanned vehicle 20. In other words, the loading point 12 indicates the position of a vessel (that which is loaded with a load) provided for the unmanned vehicle 20, and that of the bucket of the loading machine 30. In one form of single-side loading, the unmanned vehicle 20 is traveled to the front of the loading machine 30 for making a loading operation.
In this case, the unmanned vehicle 20 is led from the entrance point 11 to the loading point 12 through the waiting point 14 or a switch-back point 13 in the vicinity of the loading point 12. The waiting point 14 is a site where the unmanned vehicle 20 is stopped for waiting until it receives an instruction from the loading machine 30. In addition, the waiting point 14 can be a point which is the switch-back point 13 where, after having traveled in the forward travel mode, the unmanned vehicle 20 makes a switch-back operation for making an approach to the loading point 12 of the loading machine 30 in the backward travel mode. However, depending upon the form of loading, the switch-back is not always required. For example, the unmanned vehicle 20 may draw a circular arc from the entrance point 11 toward the loading machine 30 to reach the loading point 12. In addition, as described above, the switch-back point 13 may be identical to the waiting point 14.
The loading machine 30 excavates a working face 1a in the loading site 1 by use of the working machine 30C mounted to the upper slewing structure 30B. As the working face 1a, a scarp in the working site in a mine, or the like, is assumed. And, by the operator of the loading machine 30 operating an operation lever (not shown), the upper slewing structure 30B is slewed with respect to the base carrier 30A to position the working machine 30C at the loading point 12 for loading a load onto the unmanned vehicle 20.
At the completion of the loading operation, the unmanned vehicle 20 leaves the loading point 12 in accordance with a travel command for traveling toward the exit point 15 of the loading site 1.
In doing such a series of operations, the operator of the loading machine 30 gives the following instructions to the unmanned vehicle 20. In the unmanned vehicle drive system, the contents of an instruction of the operator are transmitted to a supervising apparatus 40 (not shown) in radio communication, and from the supervising apparatus 40, a travel command is given to the unmanned vehicle 20 in radio communication. By the operator operating a particular switch or button provided in the inside of the driver's cab of the loading machine 30, an instruction (electrical signal) in correspondence with the operation of the operator is converted into a radio signal for use in radio communication, which can be transmitted to the supervising apparatus 40, using a communication device provided for the loading machine 30.
a) Instruction of Position Setting of Loading Point 12
The loading point 12 is successively varied with the loading machine 30 being traveled and moved, or with the working machine 30C being slewed and stopped to be repositioned.
Position setting of the loading point 12 is instructed by the operator making an operation to position the bucket mounted to the working machine 30C at a desired point, and the operator depressing a “spot button” provided in the inside of the driver's cab of the working machine 30C. Once position setting of the loading point 12 is instructed, the supervising apparatus 40 uses the bucket position of the working machine 30C as the position of the loading point 12 for generating a travel route 10 to lead the unmanned vehicle 20 to the loading point 12.
b) Instruction of Approach to Loading Point 12
While the unmanned vehicle 20 is stopped at the waiting point 14 as described above, it cannot travel through an interval from the waiting point 14 to the loading point 12, unless there is given an instruction of approach to the loading point 12. The travel route from the waiting point 14 to the loading point 12 is referred to as the “final approach 16”. An instruction of approach to the loading point 12 is given to the unmanned vehicle 20 with the operator depressing a “come-in button” provided in the driver's cab of the loading machine 30. On the basis of an electrical signal generated with the “come-in button” being depressed, the communication device loaded in the loading machine 30 transmits a radio signal (a signal giving the instruction of approach) to the unmanned vehicle 20, and the unmanned vehicle 20 receives that radio signal by the communication device loaded in the unmanned vehicle 20. In this way, when the unmanned vehicle 20 receives the instruction of approach to the loading point 12, the unmanned vehicle 20 is traveled from the waiting point 14 to the loading point 12 along the final approach 16.
c) Instruction of Withdrawal from Loading Point 12
Once the loading operation has been completed, in order to allow making an operation of loading a load onto the unmanned vehicle 20 which would subsequently approach to the loading site 1, it is necessary to cause the unmanned vehicle 20 currently positioned at the loading point 12 to withdraw from the loading point 12. Withdrawal from the loading point 12 is instructed by the operator depressing a “go-button” provided in the inside of the driver's cab of the loading machine 30. When the unmanned vehicle 20 receives an instruction of withdrawal from the loading point 12, the unmanned vehicle 20 leaves from the loading point 12 to be traveled toward the exit point 15 of the loading site 1. This instruction of withdrawal of the unmanned vehicle 20 is also executed by radio communication between the loading machine 30 and the unmanned vehicle 20 as is the case with the instruction of approach as described above.
Hereafter, to the unmanned vehicle 20 which would subsequently approach to the loading site 1, the same processing is performed. So long as the loading point 12 is not varied, and the travel route 10 is not varied, due to a movement of the loading machine 30, or the like, the operator of the loading machine 30 need not operate the “spot button”, and by simply repeating the button operation of the “come-in button” and the “go-button”, the operator can continuously perform a loading operation on the respective unmanned vehicles 20.
However, with the single-side loading, the waiting time of the unmanned vehicle 20 which would subsequently go over to the loading point 12 is increased, thereby the productivity being lowered. Then, the “both-side loading” is widely accepted, because it involves less waiting time of the unmanned vehicle 20 which would go over to the loading point 12, thereby allowing improvement in productivity to be expected.
(Both-Side Loading)
FIG. 1 illustrates a case where both-side loading is performed in the loading site 1. In both-side loading, a left loading point 12L (left loading) and a right loading point 12R (right loading) are set for the loading point 12. The travel route 10 in the case of both-side loading is defined like the travel route 10 in the case of single-side loading. However, when it is necessary to discriminate between “left” and “right” for the travel route 10, the loading point 12, the final approach 16, and the exit course 17, the letters “L” and “R” will be provided after the respective numerical references, for convenience of explanation.
The left loading point 12L is a loading point where the direction of approach of the unmanned vehicle 20 to the loading machine 30 is leftward, while the right loading point 12R is a loading point where the direction of approach of the unmanned vehicle 20 to the loading machine 30 is rightward. The both-side loading is a loading operation in which the unmanned vehicle 20 is caused to approach to any of the left and right side of the loading machine 30, and therefore the loading is performed more continuously, resulting in the waiting time of the unmanned vehicle 20 being reduced, and thus the productivity being increased.
In the both-side loading, the operator gives the following instructions to the unmanned vehicle 20 of the loading machine 30. The contents of the instruction of the operator are transmitted to the supervising apparatus 40 (not shown) in a radio signal, and from the supervising apparatus 40, are given to the unmanned vehicle 20 as a travel command in a radio signal.
a) Instruction of Position Setting of Left Loading Point 12L or Right Loading Point 12R
In the inside of the driver's cab of the loading machine 30, there are provided a “left-right instruction button” for instructing the left loading point 12L (left loading) or the right loading point 12R (right loading). The “left-right instruction button” may be separately provided as that for left instruction and that for right instruction, or may be a single toggle switch which allows either of the left and right instructions to be given. The operator operates the operation lever to operate the upper slewing structure 30B or the working machine 30C such that the bucket of the working machine 30C is positioned at a desired loading point. Thereafter, the operator depresses the “left-right instruction button” to select the side on which the loading point 12 of the unmanned vehicle 20 is to be set (the side on which the travel route 10 is to be generated). Further, in order to define the bucket of the working machine 30C as the position of the loading point, the operator depresses the “spot button” for instructing position setting of the loading point 12. Assuming that, for example, the “left loading” has been instructed by use of the “left-right instruction button”, the bucket position of the working machine 30C at the time when the “spot button” has been depressed is set as the position of the left loading point 12L. And, a new travel route 10L leading to the set left loading point 12L is generated by the supervising apparatus 40.
b) Instruction of Approach to Left Loading Point 12L or Right Loading Point 12R
The operator depresses the “left-right instruction button” to select the side on which there exists the loading point 12 which is to be approached. Further, the operator depresses the “come-in button” to instruct approach to the loading point 12 on that selected side. Assuming that, for example, the “left loading” has been instructed by use of the “left-right instruction button”, a travel command is given to the unmanned vehicle 20 which exists on the travel route 10L leading to the “left loading point 12L”, and the unmanned vehicle 20 is traveled from the waiting point 14 to the left loading point 12L through the final approach 16L.
c) Instruction of Withdrawal from Left Loading Point 12L or Right Loading Point 12R
The operator of the loading machine 30 depresses the “left-right instruction button” to select the side on which there exists the loading point 12 from which the unmanned vehicle 20 is to withdraw. Further, the operator depresses the “go-button” to instruct withdrawal of the unmanned vehicle 20 from the loading point 12 on that selected side. Assuming that, for example, the “left loading” has been instructed, a travel command is given to the unmanned vehicle 20 which exists at the “left loading point 12L”, and the unmanned vehicle 20 leaves the left loading point 12L to be traveled toward the exit point 15 of the loading site 1 through the exit course 17L.
In the patent document 1, there is disclosed an invention with which, every time the loading machine is moved, the position of the loading point is automatically found, and a travel route allowing the unmanned vehicle to travel to that loading point is generated.    Patent document: Japanese Patent Application Laid-open No. H08-263138