Abstract:
A transport vehicle equipped with a current collector, includes: a vessel to load a load; a current collector that extends to receive electric power from an overhead line and contracts and retracts so as to be disposed away from the overhead line; and a vehicle body that rotationally drives driving wheels by at least one of the electric power from the current collector and a self-propelled driving source and on which the vessel is placed; a pantograph position detector that detects a relative position of the current collector and the overhead line; and a control device that controls a driving direction of the vehicle body or gives an instruction of information with which a direction in which the vehicle body is to be operated can be recognized, so that the relative position is brought to a position where the current collector and the overhead line are connected.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is related to co-pending application: “TRANSPORT VEHICLE EQUIPPED WITH CURRENT COLLECTOR” filed even date herewith in the names of Masanori Tojima, Kouichi Yamashita, Tsugio Sudou and Koji Takeda as a national phase entry of PCT/JP2012/061916, which application is assigned to the assignee of the present application and is incorporated by reference herein. 
     FIELD 
     The present invention relates to a transport vehicle equipped with a current collector. 
     BACKGROUND 
     There is disclosed a transport vehicle of a trolley assist system, which travels under its own power by driving an electric motor with an electric power generated by an in-vehicle engine generator in a normal section, but, in some sections such as a sloping road, collects current from a trolley line (overhead line) suspended above the ground using a pantograph mounted on the vehicle so as to drive the electric motor by using the current instead of the power source of the engine generator (Patent Literature 1). 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: Unexamined Japanese Utility Model No. 60-181104 
       
    
     SUMMARY 
     Technical Problem 
     The pantograph (current collector) is in contact with the overhead line, but it may be stuck with the overhead line and may be damaged. It is an object of the present invention to provide a transport vehicle equipped with a current collector that suppresses damage of a current collector when electric power is collected from an overhead line. 
     Solution to Problem 
     According to the present invention, a transport vehicle equipped with a current collector, comprises: a vessel to load a load; a current collector that extends to receive electric power from an overhead line and contracts and retracts so as to be disposed away from the overhead line; a vehicle body that rotationally drives driving wheels by at least one of the electric power from the current collector and a self-propelled driving source and on which the vessel is placed; a pantograph position detector that detects a relative position of the current collector and the overhead line; and a control device that controls a driving direction of the vehicle body or gives an instruction of information with which a direction in which the vehicle body is to be operated can be recognized, so that the relative position is brought to a position where the current collector and the overhead line are connected. 
     According to the present invention, the vehicle body includes an obstacle detector to detect an obstacle on a traveling path, and when the obstacle detector detects an obstacle on the traveling path, the control device controls the current collector to contract and retract. 
     According to the present invention, when the pantograph position detector detects that the current collector is deviated from the overhead line, the control device controls the current collector to contract and retract. 
     According to the present invention, when there is the overhead line in the traveling path along which the vehicle body is planned to drive, and the pantograph position detector recognizes a relative position between the current collector and the overhead line, the control device controls the current collector to extend and receive the electric power from the overhead line. 
     According to the present invention, the vehicle body is a manned transport vehicle, and the information is displayed on a display unit. 
     The present invention can suppress damage of a current collector when electric power is collected from an overhead line. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating a dump truck using a current collector according to the present embodiment. 
         FIG. 2  is an explanatory diagram illustrating a stretched state of the current collector of  FIG. 1 . 
         FIG. 3  is a too view of  FIG. 1 . 
         FIG. 4  is an explanatory diagram illustrating an example of a self-propelled driving source of the dump truck according to the present embodiment. 
         FIG. 5  is an explanatory diagram illustrating an example of a control block of the dump truck according to the present embodiment. 
         FIG. 6  is an explanatory diagram illustrating an example of a travelling path of the dump truck according to the present embodiment. 
         FIG. 7  is a flowchart illustrating an example of a control procedure of the dump truck according to the present embodiment. 
         FIG. 8  is a flowchart illustrating an example of a control procedure of the dump truck according to the present embodiment. 
         FIG. 9  is an explanatory diagram illustrating an example of travelling-path information of the dump truck according to the present embodiment. 
         FIG. 10  is a flowchart illustrating another example of a control procedure of the dump truck according to the present embodiment. 
         FIG. 11  is a side new illustrating the dump truck using the current collector according to the present embodiment. 
         FIG. 12  is an explanatory diagram illustrating a stretched state of the current collector of  FIG. 11 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiment. In addition, elements described below include those that are easily conceived by a person skilled in the art and that are substantially the same. Further, the elements described below can be properly combined. Furthermore, various omissions, displacements, modifications of the elements can be performed without departing from the scope of the present invention. 
     &lt;Unmanned Dump Truck&gt; 
       FIG. 1  is a perspective view illustrating a dump truck using a current collector according to the present embodiment.  FIG. 2  is an explanatory diagram illustrating a stretched state of the current collector of  FIG. 1 .  FIG. 3  is a top view of  FIG. 1 . A dump truck  1  is a transport vehicle equipped with current collector of so-called trolley assist system by driving an electric motor with an electric power fed by the current collector to rotationally drive driving wheels in an overhead line section. 
     The dump truck  1  is a transport vehicle equipped with current collector including a vehicle body  3  that includes wheels  31 , driving wheels  32 , and a chassis  30 , a vessel  5  placed on the chassis  30  of the vehicle body  3 , a pantograph  7 , and an input/output device group  9 . In addition, the dump truck  1  is an unmanned dump truck that travels as an unmanned transport vehicle which is not equipment with a cab. The vehicle body  3  is a hybrid vehicle, which generates power by using a fuel and also generates the power by using the electric power. The vehicle body  3  makes a travelling possible by transmitting the generated power to the driving wheels  32 . The wheels  31  and the driving wheels  32  are attached to the chassis  30 . The dump truck  1  is used in, for example, a mine or the like. 
     The vessel  5  is a loading platform for loading loads and is disposed on the chassis  30  of the vehicle body  3 . On the vessel  5 , as the loads, unloading earth such as an ore, rock, or soil is loaded. The vessel  5  is tilted by a hydraulic cylinder and may thus discharge the loaded loads. Further, the vessel  5  may be a detachable configuration with respect to the chassis  30  of the vehicle body  3 . 
     The pantograph  7  is a current collector for receiving the electric power from an overhead line  8 . For example, the pantograph  7  includes a slider  71 , a first arm  72 , a second arm  73 , a pantograph control actuator  74 , and a pantograph joint  75 . In the dump truck  1  according to the present embodiment, since two overhead lines  8  are presented, two pantographs  7  are provided. 
     The slider  71  is attached to an end of the first arm  72  and is a current collecting member for receiving the electric power from the overhead line  8  by slidably coming in contact with the overhead line  8 . The first arm  72  and the second arm  73  are connected to each other using the pantograph joint  75  and have a joint structure which can follow the change in a height of the overhead line  8 . The second arm  73  is attached to the pantograph control actuator  74 . 
     The pantograph  7  is stretched by the operation of the pantograph control, actuator  74  and then is capable of receiving the electric power from the overhead line  8 . In addition, the pantograph  7  is contracted and retracted to be folded by the operation of the pantograph control actuator  74  and then is stored below the vessel  5 . The contracted and retracted pantograph  7  is disposed on an inner side of a dotted line illustrating an outline of the vessel  5  illustrated in  FIG. 3  when viewed from the top. Thus, in a case of loading or unloading the loads, such as the ore, onto or from the vessel  5 , the contracted and retracted pantograph  7  is covered with the vessel  5 . In other words, the contracted and retracted pantograph  7  is in a state in which the contracted and retracted pantograph is hidden in the vessel  5  when viewed from the to. 
     Therefore, it is possible to reduce the possibility that the loads fall from the vessel  5  and come in contact with the pantograph  7 . Further, since the pantograph  7  is covered with the vessel  5 , in a loading area to be described later, the possibility that a loading machine such as an excavator, which is used for loading the loads such as the ore on the vessel  5 , collides with the pantograph  7  is reduced. As a result, it is possible to reduce the possibility that the damage occurs in the pantograph  7 . In addition, the dump truck  1  mostly runs on outdoors or parks in the outdoors. The dump truck  1  can inhibit effects caused by rain or the like on the pantograph  7 , since the contracted and retracted pantograph  7  is hidden in the vessel  5  when viewed from the top. As a result, the dump truck  1  can reduce the risk of failure of the pantograph  7 . Further, the dump truck  1  has no cab, and the vessel  5  can cover the vehicle body  3 . Therefore, the vessel  5  is substitutive for a hangar. As a result, it is also possible to reduce the possibility that the vehicle body  3  is likely to be failed. 
     Preferably, the pantograph  7  has a structure in which the first arm  72  is folded in the second arm  73 . The second arm  73  has a concave portion and the first arm  72  may be accommodated in the concave portion. For this reason, the protrusion of the pantograph  7  becomes less at the time of storing the pantograph  7 . In addition, since the dump truck  1  has no cab, it is easy to secure a region for storing the pantograph  7  below the vessel  5 . 
     The pantograph  7  is arranged on at least a front side in a moving direction of the chassis  30 . Further, more preferably, the pantograph  7  is also arranged on a rear side of the moving direction of the chassis  30 . That is, the pantograph  7  is disposed on both sides of the vehicle body  3  in a direction parallel to the moving direction of the vehicle body  3 . Thus, when the vehicle body  3  travels along a sloping road, it is possible to stretch the pantograph  7  of an inclined upper side of the sloping road and then to receive the electric power from the overhead line  8  without the operation of reversing the vehicle body  3 . As a result, even if the loads fall from the vessel  5  because of an inclination of the sloping load, the possibility that the loads collide with the pantograph  7  is reduced. Furthermore, the pantograph  7  may be disposed on at least one side of the vehicle body  3  in a direction perpendicular to the moving direction of the vehicle body  3 , and preferably, may be disposed on both sides thereof, respectively. 
     The input/output device group  9  is provided with a pantograph position detector  91  which detects a position of the pantograph  7 , an obstacle detector  92  which detects obstacles on the traveling path of the vehicle body  3 , a vehicle body position measuring device  95  which measures a present position of the vehicle body  3 , and a communication device  93  which performs a radio communication with a central management control equipment to be described later. 
     The pantograph position detector  91  is an image pickup device, for example, such as a camera. Alternatively, the pantograph position detector  91  may be a laser positioning device or an ultrasonic positioning device. It is preferable to be disposed at a plurality of positions with predetermined intervals. Thus, it is possible to grasp a contact state of the slider  71  of the pantograph  7  with the overhead line  8 . 
     The obstacle detector  92  is, for example, a millimeter-wave radar device and may detect the position of the obstacle by transmitting a radio wave of a millimeter waveband and receiving a reflective wave reflected from the obstacle. The vehicle body position measuring device  95  is a position measuring device such as a Global Positioning System (GPS). 
     The dump truck  1  stores traveling path information which holds information on the moving direction or speed on map in in a memory within a control device to be described later. The dump truck  1  determines the moving direction or the speed based on the traveling path information and the present position information obtained from the vehicle body position measuring device  95  and then travels. In addition, the dump truck  1  may also be autonomous unmanned dump capable of determining independently a traveling condition based on information of the input/output device group  9 . 
     &lt;Self-Propelled Driving Source&gt; 
       FIG. 4  is an explanatory diagram illustrating an example of a self-propelled driving source of the dump truck according to the present embodiment. As illustrated in  FIG. 4 , the vehicle body  3  includes a control device  4 , a generator  35 , an engine  34  serving as internal-combustion engine, a steering  36 , and a motor  33  on the chassis  30 . Further, the generator  35  is connected to the engine  34  and is the self-propelled driving source for generating the electric power by power of the engine  34 . 
     In addition, the control device  4  transfers the electric power generated from the generator  35  to the motor  33  and the steering  36 . The motor  33  is an in-wheel motor disposed within the driving wheel  32 . Further, the motor  33  is also disposed in the wheel  31  so that the wheel  31  serves as the driving wheel, and thus the vehicle body  3  may become four-wheel-drive. 
     The steering  36  includes, for example, an electric motor and steers the direction of the wheel  31  in accordance with the control of the control device  4 . In addition, the control device  4  transfers the electric power from the above-described pantograph  7  to the motor  33  and the steering  36 . The control device  4  causes the vehicle body  3  to travel, independently by supplying the electric power generated from the generator  35  to the motor  33 . 
     In addition, the control device  4  collects the current from the overhead line  8  by the pantograph  7  and supplies the electric power to the motor  33  from the pantograph  7  in place of the generator  35  to cause the traveling of the vehicle body  3 . Moreover, the control device  4  collects the current from the overhead line  8  by the pantograph  7  and supplies the electric power from the pantograph  7  together with the electric power of the generator  35  to the motor  33  to cause the traveling of the vehicle body  3 . 
     &lt;Control of Dump Truck&gt; 
       FIG. 5  is an explanatory diagram illustrating an example of a control block of the dump truck according to the present embodiment.  FIG. 6  is an explanatory diagram illustrating an example of the traveling path of the dump truck according to the present embodiment.  FIGS. 7 and 8  are flowcharts illustrating an example of a control procedure of the dump truck according to the present embodiment. The control device  4  is connected to the pantograph position detector  91 , the obstacle detector  92 , the vehicle body position measuring device  95 , the communication device  93 , the motor  33 , the steering  36 , and the pantograph control actuator  74 . The control device  1  is a computer system including a CPU (Central Processing Unit) and memory. The control device  4  includes a traveling path information generating unit  41 , a traveling control unit  42 , a pantograph control unit  43 , and a communication control unit  44 . 
     The traveling path of the dump truck  1  illustrated in  FIG. 6  has, for example, an overhead-lined section  5  in which the overhead line  8  is laid and self-propelled sections E 1  and E 2  in which the overhead line is not laid. For example, the dump truck  1  is shipped with loads  50  by a loading machine  59  at a loading area  51 . 
     The dump truck  1  travels freely along the self-propelled section E 2  and reaches the overhead-line section T. The dump truck  1  stretches the pantograph  7  of the inclined upper side of the sloping road in the overhead-lined section. T and travels in a direction of arrow V for receiving the electric power from the overhead line  8 . Then, the dump truck  1  freely travels along the self-propelled section  52  and discharges the loads  50  by tilting the above-described vessel  5  using a hydraulic cylinder at an earth unloading area  52  which is a destination. 
     A central management control equipment  6  located in a remote place from the traveling path of the dump truck  1  includes a central control device  61  and a communication device  62 . The central control device  61  is actuated by an operator and manages an operation status of the dump truck  1 . The communication device  62  performs a radio communication of radio wave W between the central control device  61  and the dump truck  1  to transmit and receive a variety of information. Thus, the dump truck  1  and the central management control equipment  6  act as a transport system. As a result, the operation status of the dump truck  1  is managed by the central management control equipment  6 . This transport system can reduce operator personnel. 
     The control procedure illustrated in  FIG. 7  will be described below. When the control device  4  obtains the position information from the vehicle body position measuring device  95 , the obtained position information is transmitted to the central management control equipment  6  through the communication device  62  and the communication device  93 . As a result, the central management control equipment  6  can obtain the operation status information of the dump truck  1 . In addition, the transport system can deliver the map information, which is calculated by the central control device  61  of the central management control equipment  6  based on the operation status information of the dump truck  1 , to the control device  4  of the dump truck  1  through the communication device  62  and the communication device  93 . 
     The traveling bath information generating unit  41  of the control device  4  generates traveling path information based on the map information which is obtained from the communication device  93  or stored previously (step S 1 ). The traveling path information includes the map information and the information of the traveling path as a scheduled course along which the dump truck  1  travels. In addition, the traveling path information generates as the traveling path by attaching identification information of the overhead-lined section on which the overhead line  8  is laid and the self-propelled section on which the overhead line  8  is not laid to the map information. For example, the traveling path information is the information of the scheduled traveling path along which the dump truck  1  travels and in which the overhead-lined section T and the self-propelled sections E 1  and E 2  illustrated in  FIG. 6  are identified. 
     The control device  4  stores the traveling path information in the memory. Next, the traveling control unit  42  of the control device  4  determines the moving direction or the speed based on the traveling path information and controls the motor  33  and the steering  36 . When the control device  4  obtains the position information from the vehicle body position measuring device  95 , the obtained position information is transmitted to the central management control equipment  6  through the communication device  62  and the communication device  93 . 
     The control device  4  compares the traveling path information with the present position information of the dump truck  1  of the vehicle body position measuring device  95 . When the control device  4  determines that the present position of the dump truck  1  is not in the overhead-lined section T (No in step S 2 ), the pantograph control unit  43  controls the pantograph control actuator  74  to lower the pantograph  7  (step S 3 ). As a result, the actuator  74  is contracted and retracted to be folded and is in a state in which the actuator is stored below the vessel  5 . 
     The traveling control unit  42  controls the motor  33  and the steering  36  by the self-propelled driving source, based on the traveling path information. Thus, the dump truck  1  travels (step S 4 ). When control device  4  obtains the position information from the vehicle body position measuring device  95 , the obtained position information is transmitted to the central management control equipment  6  through the communication device  62  and the communication device  93 . 
     When the control device  4  determines that the dump truck  1  does not reach the destination, for example, the earth unloading area  52  by comparing the traveling path information with the present position information of the dump truck  1  of the vehicle body position measuring device  95  (No in step S 5 ), the procedure returns to step S 2 . The control device  4  causes the work of the dump truck  1  to be ended when determining that the dump truck  1  reaches the destination (Yes in step S 5 ). 
     When the control device  4  determines that the present position of the dump truck  1  is in the overhead-lined section T (Yes in step S 2 ), the control device confirms the position of the overhead line  8  by the pantograph position detector  91  (step S 6 ). 
     Next, the traveling control unit  42  controls the steering  36  (step S 7 ) and controls the traveling direction of the vehicle so that the pantograph is placed below the overhead line  8 . Then, the pantograph control unit  43  controls the pantograph control actuator  74  such that the pantograph  7  is raised (step S 8 ) and the pantograph  7  stretches to be in the state capable of receiving the electric power from the overhead line  8 . Accordingly the dump truck  1  can receive the electric power from the overhead line  8  by stretching automatically the pantograph  7 . The traveling control unit  42  performs trolley assist traveling which controls the motor  33  and the steering  36  by the electric power from the overhead line  8  based on the traveling path information (step S 9 ). 
     Here, the control device  4  obtains a relative position between the pantograph  7  and the overhead line  8  from the pantograph position detector  91  and recognizes using an image. The traveling control unit  42  operates the steering  36  in a direction to reduce a deviation amount between the slider  71  of the pantograph  7  and the overhead line  8  such that the pantograph  7  seizes on the overhead line  8  and the pantograph  7  is not deviated from the overhead line  8 . Thus, in the overhead-lined section T, the ratio that the pantograph  7  of the dump truck  1  seizes on the overhead line  8  increases and thus can inhibit the use of the self-propelled driving source. Furthermore, the operation of the steering  36  due to the above-described traveling control unit  42  may be performed at all times after the pantograph  7  seizes on the overhead line  8  and may also be performed at the time of exceeding the predetermined deviation amount which is previously set. 
     For example, the position of the overhead line  8  is substantially constant, but there is a concern that the position deviation of the overhead line  8  is generated by wind. The dump truck  1  takes the position deviation of the overhead line  8  as a relative position between the pantograph  7  and the overhead line  8 , and the control device  4  modifies the steering  36  of the vehicle body  3 , thereby correcting the position of the pantograph  7 . As a result, the ratio that the pantograph  7  seizes on the overhead line  8  increases. Since the pantograph position detector  91  always recognizes the relative position between the pantograph  7  and the overhead line  8 , the control device  4  can control the steering  36  so as to modify the relative position between the pantograph  7  and the overhead line  8 , before the pantograph  7  hooks the overhead line  8 . 
     In addition, the control device  4  continues the trolley assist traveling (step S 9 ) when determining that the pantograph  7  seizes on the overhead line  8  (No in step S 10 ). 
     The flowchart of  FIG. 8  illustrates an example of the control procedure of the dump truck for illustrating step S 10  in more detail. For example, the obstacle detector  92  detects the obstacle (step S 101 ). The control device  4  transmits information on the obstacle to the central management control equipment  6  through the communication device  62  and the communication device  93 . Here,  FIG. 9  is an explanatory diagram illustrating an example of the traveling path information of the dump truck according to the present embodiment. 
     In  FIG. 9 , for example, the dump truck  1  is scheduled to travel along the overhead-lined section T from a traveling position P 1  to a traveling position P 3  through a trouble-occurrence section H, in the traveling path information generated in step S 1 . The obstacle detector  92  detects the obstacle in the trouble-occurrence section H (step S 101 ). When the control device  4  obtains the information on the obstacle, the obtained information is transmitted to the central management control equipment  6  through the communication device  62  and the communication device  93 . 
     The control device  4  determines whether or not the detected obstacle is on the scheduled traveling course. When the control device  4  determines that the obstacle is not on the scheduled traveling course (No in step S 102 ), the obstacle detector  92  continues the obstacle detection of step S 101 . When the control device  4  determines that the obstacle is on the scheduled traveling course (Yes in step S 103 ), the control device  4  determines that the obstacle is present (Yes in step S 103 ). As a result, the control device  4  determines that the pantograph  7  does not seize on the overhead line  8  (Yes in step S 10 ), and thus the procedure proceeds to step S 11 . The control device  4  re-creates the traveling path information of a detour position P 2  illustrated in  FIG. 9  (step S 11 ). 
     Alternatively, the central control device  61  determines that the obstacle is present (Yes in step S 103 ) and may transmit the obstacle information to the dump truck  1 . In this case, the control device  4  receives the obstacle information from the central control device  61  through the communication device  62  and the communication device  93  and determines that the pantograph  7  does not seize on the overhead line  8  (Yes in step S 10 ), and thus the procedure proceeds to step S 11 . 
     Since the detour position P 2  is a self-propelled section E 3  without the overhead line  8 , the control device  4  lowers the pantograph  7  (step S 3 ). The pantograph control unit  43  controls the pantograph control actuator  74  to lower the pantograph  7  (step S 3 ). As a result, the pantograph  7  is contracted and retracted to be folded and is in the state which is stored below the vessel  5 . The traveling control unit  42  controls the motor  33  and the steering  36  by the self-propelled driving source based on the re-created traveling path information in step S 11 . Thus, the dump truck  1  travels (step S 4 ). In this way, even though the dump truck  1  is the unmanned transport vehicle in which the vehicle body  3  has no cab, it can travel so that the pantograph  7  does not seize on the overhead line  8  while avoiding the obstacle at the same time. That is, the dump truck  1  can continuously travel even in a condition where the determination of the operator is absent. When the control device  4  obtains the position information from the vehicle body position measuring device  95 , the obtained position information is transmitted to the central management control equipment  6  through the communication device  62  and the communication device  93 . 
     The control device  4  compares the traveling path information with the present position information of the dump truck  1  of the vehicle body position measuring device  95 . At this time, when the control device  4  determines that the dump truck  1  does not reach the destination, for example, the earth unloading area  52  (No in step S 5 ), the procedure returns to to  22 . 
     When the control device  4  obtains the traveling position P 3  as the position information from the vehicle body position measuring device  95 , the control device  4  determines that there is the overhead-lined section T by comparing the traveling path information with the traveling position P 3  serving as the present position information (Yes in step S 2 ). Then, the procedure repeats steps after step S 6 . 
       FIG. 10  is a flowchart illustrating another example of the control procedure of the dump truck according to the present embodiment. The flowchart of  FIG. 10  illustrates another example of the control procedure of the dump truck for illustrating step S 10  in more detail. For example, the pantograph position detector  91  detects the position of the pantograph  7  (step S 111 ). Thus, the connection state between the slider  71  of the pantograph  7  and the overhead line  8  is detected. 
     The control device  4  transmits the information on the connection state between the slider  71  of the pantograph  7  and the overhead line  8  to the central management control equipment  6  through the communication device  62  and the communication device  93 . When the control device  4  determines that the connection state between the slider  71  of the pantograph  7  and the overhead line  8  is not deviated (No in step S 112 ), through image analysis, the pantograph position detector  91  continues the position detection of the pantograph  7  of step S 111 . 
     When the control device  4  determines that the connection state between the slider  71  of the pantograph  7  and the overhead line  8  is deviated (Yes in step S 112 ), through the image analysis, it is determined that the trouble is present (step S 113 ). As a result, the control device  4  determines the pantograph  7  does not seize on the overhead line  8  (Yes in step S 10 ), and thus the procedure proceeds to step S 11 . The control device  4  re-creates the traveling path information of the detour position P 2  illustrated in  FIG. 9  (step S 11 ). Alternatively, the control device  4  re-creates the traveling path information by setting the trouble-occurrence section H illustrated in  FIG. 9  as the self-propelled section (step S 11 ). 
     When the control device  4  determines that the connection state between the slider  71  of the pantograph  7  and the overhead line  8  is deviated, due to strong wind in the trouble-occurrence section H illustrated in  FIG. 9  (Yes in step S 112 ), it is determined that the trouble is present (step S 113 ). 
     Alternatively, the central control device  61  may determine that the trouble is present (Yes in step S 103 ) and transmit the obstacle information to the dump truck  1 . In this case, the control device  4  receives the obstacle information, from the central control device  61  through the communication, device  62  and the communication device  93  and determines that the pantograph  7  does not seize on the overhead line  8  (Yes in step S 10 ), and thus the procedure proceeds to step S 11 . 
     Next, the pantograph control unit  43  controls the pantograph control actuator  74  to lower the pantograph  7  (step S 3 ). As a result, the pantograph  7  is contracted and retracted to be folded and is in the state which is stored below the vessel  5 . 
     The traveling control unit  42  controls the motor  33  and the steering  36  by the self-propelled driving source, based on the traveling path information re-created in step S 11 . Thus, the dump truck  1  travels (step S 4 ). In this way, even though the dump truck  1  is the unmanned transport vehicle in which the vehicle body  3  has no cab, it can travel while avoiding abnormity of the overhead line  8 . That is, the dump truck  1  can continuously travel even in a condition where the determination of the operator is absent. When the control device  4  obtains the position information from the vehicle body position measuring device  95 , the obtained position information is transmitted to the central management control equipment  6  through the communication device  62  and the communication device  93 . 
     The control device  4  compares the traveling path information with the present position information of the dump truck  1  of the vehicle body position measuring device  95 . At this time, when the control device  4  determines that the dump truck  1  does not reach the destination, for example, the earth unloading area  52  (No in step S 5 ), the procedure returns to step S 2 . 
     When the control device  4  obtains the traveling position  93  as the position information from the vehicle body position measuring device  95 , the control device  4  determines that there is the overhead-lined section T by comparing the traveling path information with the traveling position P 3  serving as the present position information (Yes in step S 2 ). Then, the procedure repeats steps after step S 6 . Moreover, the pantograph  7  may be stretched in such as a way of detecting the fact that the dump truck  1  has come under the overhead line  8  by the vehicle body position measuring device  95  such as GPS rather than by the pantograph position detector  91  serving as a pantograph position detecting unit. Further, the pantograph  7  may be stretched in such as a way that the dump truck  1  receives operation signal from the central control device  61 . The above-described embodiment is described with respect to the dump truck  1  with no cab, but the dump truck may be an unmanned transport vehicle with a cab, and may be a manned dump truck which is a manned transport vehicle to be described later. 
     &lt;Manned Dump Truck&gt; 
       FIG. 11  is a side view illustrating the dump truck using the current collector according to the present embodiment.  FIG. 12  is an explanatory diagram illustrating a state in which the current collector of  FIG. 11  is stretched. A dump truck  2  is a manned dump truck provided with the chassis  30  having a cab  38 . Therefore, the vehicle body  3  of the dump truck  2  acts as a manned transport vehicle. The same reference numerals are denoted to the same members as those described above and a redundant description will be not presented. The dump truck  2  is used in a mine, for example. 
     A pantograph  70  is disposed above the cab  38  illustrated in  FIG. 11 . In addition, as illustrated in  FIG. 12 , the pantograph  70  is stretched by the operation of the pantograph control actuator  74  and then is capable of receiving the electric power from the overhead line  8 . In addition, as illustrated in  FIG. 11 , the pantograph  70  is contracted and retracted to be folded by the operation of the pantograph control actuator  74  and then is stored below the vessel  5 . The contracted and retracted pantograph  70  is disposed on the inner side in relation to the outline of the vessel  5  illustrated in  FIG. 11  when viewed from the top. Thus, in a case of loading the loads on the vessel  5 , the pantograph  7  is covered with the vessel  5 , and thus it is possible to reduce the possibility that the damage of the pantograph  7  occurs due to the falling of loads from the vessel  5 . In other words, the contracted and retracted pantograph  7  is in a state which is hidden in the vessel  5  when viewed from the top. 
     The pantograph  70  is arranged on at least the front side in the moving direction of the chassis  30 . Further, more preferably, the pantograph  70  is also arranged on the rear side of the moving direction of the chassis  30 . Thus, when the vehicle body  3  travels along the sloping road, it is possible to stretch the pantograph  70  of the inclined upper side of the sloping road and then to receive the electric power from the overhead line  8  without the operation of reversing the vehicle body  3 . As a result, due to the inclining of the sloping road, even if the loads are fallen from the vessel  5 , the possibility that the loads collide with the pantograph  70  is reduced. In addition, the dump truck  2  mostly runs on outdoors or parks in the outdoors. The dump truck  2  can inhibit effects caused by rain on the pantograph  70 , since the contracted and retracted pantograph  70  is hidden in the vessel  5  when viewed from the top. As a result, the dump truck  2  can reduce the risk of trouble of the pantograph  70 . Furthermore, the pantograph  70  may be disposed on at least one side of the vehicle body  3  in the direction perpendicular to the moving direction of the vehicle body  3 , and preferably, may be disposed on both sides thereof, respectively. 
     Next, the procedure of the dump truck  2  will be described. The operator confirms the present position of the dump truck  2  and the position of the overhead line  8 . 
     Next, the operator actuates the steering  36  and operates the vehicle so that the pantograph  7  is placed below the overhead line  8 . Then, after the operator determines that the pantograph  70  is placed below the overhead line  8 , the operator raises the pantograph  70  by actuating an operational switch of the pantograph control actuator  74  so that the pantograph  70  is stretched to be in the state capable of receiving the electric power from the overhead line  8 . Moreover, as in the above-described dump truck  1 , the pantograph  70  may be automatically stretched by the pantograph position detector  91  serving as the pantograph position detecting unit. Further, the pantograph  70  may be stretched in such as a way of detecting the fact that the dump truck  2  has come under the overhead line  8  by the vehicle body position measuring device  95  such as GPS. Further, the pantograph  70  may be stretched in such as a way that the dump truck  2  receives operation signal from the central control device  61 . 
     Here, the control device  4  obtains the relative position between the slider  71  of the pantograph  70  and the overhead line  8  from the pantograph position detector  91  and recognizes it using an image. The control device  4  instructs the information capable of recognizing the direction to actuate the steering to the operator of the cab so that the pantograph  70  seizes on the overhead line  8  and that the pantograph  70  is not deviated from the overhead line  8 . Furthermore, the instruction may be performed at all times after the pantograph  70  is seized on the overhead line  8 , or may also be performed at the time of exceeding the predetermined deviation amount which is previously set. 
     For example, the control device  4  instructs the direction to control the steering to the operator of the cab  38 , using a sound or an arrow mark or character on the screen of a monitor (display unit) installed on the cab so that the pantograph  70  seizes on the overhead line  8  and that the pantograph  70  is not deviated from the overhead line  8 . Thus, in the overhead-lined section T, the ratio that the pantograph  70  of the dump truck  1  seizes on the overhead line  8  increases and thus can inhibit the use of the self-propelled driving source. For example, the position of the overhead line  8  is substantially constant, but there is a concern that the position deviation of the overhead line  8  occurs by wind. 
     The position of the pantograph  70  is corrected in such a way that the dump truck  2  takes the position deviation of the overhead line  8  as the relative position between the pantograph  70  and the overhead line  8  and that the control device  4  instructs the traveling of the vehicle body  3 . As a result, the ratio that the pantograph  70  seizes on the overhead line  8  increases. Since the pantograph position detector  91  recognizes the relative position between the pantograph  70  and the overhead line  8  at all times, before the pantograph  70  hooks the overhead line  8 , the control device  4  can instruct the traveling so as to modify the relative position between the pantograph  70  and the overhead line  8 . Furthermore, the control device  4  may instruct the traveling direction by displaying data (image) caught with the pantograph position detector  91  serving as the pantograph position detecting unit on the monitor (display unit) instead of the arrow mark or character. Even in this case, the operator can recognize the relative position between the pantograph  70  and the overhead line  8  from the information to be displayed on the screen to modify the position deviation. 
     As in the above-described dump truck  1 , the vehicle body  3  of the dump truck  2  is provided with the obstacle detector  92  which detects the obstacle on the traveling path. In addition, the control device  4  may contract and retract the pantograph  70  serving as the current collector when the obstacle detector  92  detects the obstacle on the traveling path. 
     As in the above-described dump truck  1 , the dump truck  2  is provided with the pantograph position detector  91 . In addition, the control device  4  may contract and retract the pantograph  70  when the pantograph position detector  91  detects that the pantograph  70  is deviated from the overhead line  8 . 
     In the dump truck  2 , as in the above-described dump truck  1 , when the overhead line  8  is present on the traveling path along which the vehicle body is going to travel, if the pantograph position detector  91  recognizes the relative position between the pantograph  70  and the overhead line  8 , the control device  4  may allow the pantograph  70  to be stretched so as to receive the electric power from the overhead line  8 . Thus, the dump truck  2  can automatically receive the electric power from the overhead line  8 . As a result, the burden of the operator is alleviated. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1 ,  2  DUMP TRUCK 
               3  VEHICLE BODY 
               4  CONTROL DEVICE 
               5  VESSEL 
               6  CENTRAL MANAGEMENT CONTROL EQUIPMENT 
               7 ,  70  PANTOGRAPH (CURRENT COLLECTOR) 
               8  OVERHEAD LINE 
               91  PANTOGRAPH POSITION DETECTOR 
               92  OBSTACLE DETECTOR