COMMUNICATION SYSTEM

BACKGROUND OF THE INVENTION

Field of the Invention

The present application relates to a communication system, and in particular relates to a communication system that is used for remotely controlling a mobile crane.
The present application claims priority on Japanese Patent Application No. 2010-013539, filed January 25, 2010, the content of which is incorporated herein by reference.

Description of Related Art

As a crane that transports containers that are stored in a container yard or the like, there is conventionally known a mobile crane that is self propelled along a running lane of a container yard. Also, remotely operating a mobile crane by performing wireless communication with the mobile crane is known.

As an example of a system for remotely operating a mobile crane, Japanese Unexampled Patent Application No. 2006-180141 (hereinbelow Patent Document 1) discloses a wireless communication system that performs wireless communication between an antenna that is provided on a mobile crane and a base station that is provided in a container yard, and between an automated guide vehicle that conveys a container and the base station that is provided in a container yard.

In the wireless communication system that is disclosed in Patent Document 1, the antenna for the mobile crane and the antenna for the automated guide vehicle are arranged at separate positions in the height direction of the mobile crane. For this reason, it is possible to suppress interference of electromagnetic waves between the wireless communication channel that is allocated to the mobile crane and the wireless communication channel that is allocated to the automated guide vehicle. As a result, it is possible to remotely operate the mobile crane using wireless communication and it is possible to remotely operate the automated guide vehicle using wireless communication.

However, in the wireless communication system that is disclosed in Patent Document 1, there is a case of the wireless communication band being insufficient when the data that is being transmitted and received between the mobile crane and the base station increases in size. In this case, it is necessary to allocate a plurality of wireless communication channels to one mobile crane. At such a time, when a plurality of mobile cranes are provided in a container yard, there is the risk of wireless communication channels that can be used being insufficient.

Japanese Unexamined Patent Application No. 2007-31102 (hereinbelow referred to as Patent Document 2) discloses a remote operation system that is provided with a receiving portion that receives video signals related to the cargo handling state transmitted from mobile cranes and a monitor that displays an image based on the received video signals.
In the remote operation system of Patent Document 2, a wireless communication channel for transmitting image signals that are transmitted from a remote crane and a wireless communication channel for transmitting command signals for controlling the running of the mobile crane are individually allocated.

However, in the remote operation system that is disclosed in Patent Document 2, there is a need to allocate two types of wireless communication channels to one mobile crane. For this reason, it is necessary to allocate a plurality of wireless communication channels of different frequency bands in order to suppress interference of wireless communication between a plurality of mobile cranes, and there are cases of the useable wireless communication channels being insufficient.

The present invention was achieved in view of the above circumstances, and has as its object to provide a communication system that can suppress an increase in the number of wireless communication channels used for communicating with mobile cranes.

SUMMARY OF THE INVENTION

In order to solve the abovementioned issues, this invention proposes the following means.
The communication system of the present invention is a communication system that performs communication between a mobile crane that travels in a lane of a container yard and a remote operation unit for remotely operating the mobile crane by receiving a detection signal that indicates the running state of the mobile crane, consisting of: a converter that converts the detection signal to IP data; a leakage coaxial cable that is provided in the travel lane along the travel direction of the mobile crane in order to transmit and receive the IP data; and an antenna that is provided on the mobile crane and that transmits and receives the IP data to and from the leakage coaxial cable.

The remote operation unit may transmit to the mobile crane a command signal that instructs movement of the mobile crane between the mobile crane and the remote operation unit; and the converter may convert the command signal to IP data.
The IP data may have a crane ID that identifies the mobile crane; the remote operation unit may have an operation console in order to remotely operate the mobile crane corresponding to each of the mobile cranes; and the remote operation unit, by deciding the operation console based on the crane ID, may transmit and receive IP data
between the operation console and the mobile crane.

The leakage coaxial cable may be disposed along a trolley line for feeding electrical power to the mobile crane.

The antenna may be fixed to a power feed trolley that is electrically connected to the trolley line that is coupled to the mobile crane.

EFFECT OF THE INVENTION

According to the communication system of the present invention, since a remote operation unit and mobile cranes communicate using IP data by means of radio waves that are transmitted from a leakage coaxial cable that is provided in a travel lane along the travel direction that each mobile crane travels, it is possible to suppress an increase in the number of wireless communication channels used for communicating with mobile cranes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall view of a crane system that is provided with the communication system of the first embodiment of the present invention.
FIG. 2 is a front view that shows the constitution of a portion of the mobile crane and the container yard in the same crane system.
FIG. 3 is a schematic view for describing the outline configuration of the communication system of the same embodiment.
FIG. 4 is a system configuration diagram that shows the configuration of the communication system of the same embodiment.
FIG. 5 is a sequence diagram for describing the operation of the communication system of the same embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Herein below, a crane system 1 having with a communication system 200 of one embodiment of the present invention shall be described.

FIG. I is an overall view that shows the crane system 1. Also, FIG. 4 is a system configuration diagram that shows the constitution of the communication system 200 in the crane system 1.

As shown in FIG. 1 and FIG. 4, the crane system 1 is provided with a plurality of travel lanes L that are arranged on a road surface R in a container yard Y, a plurality of mobile cranes 10 that travel in each travel lane L, a plurality of power feeding mechanisms 2 that supply electrical power to each mobile crane 10, a remote operation room 40 for remotely operating the mobile cranes 10, and a communication system 200 for performing wireless communication with the mobile cranes 10.

Note that FIG. 1 shows three travel lanes L and three mobile cranes 10 that are arranged in the travel lanes L as one example, but the number of travel lanes L and the number of mobile cranes 10 is not limited to the number shown in FIG. 1.

Next, the mobile crane 10 shall be described.

The mobile crane 10 is a crane for conveying containers 100 that are stored in a container yard Y by traveling in each travel lane L in the container yard Y and loading and unloading containers 100 that are carried in and carried out by a trailer or automated guide vehicle (not shown) that transports the containers 100. The mobile crane 100 of the present embodiment is a rubber tired gantry crane.

FIG. 2 is a front view that shows the constitution of one portion of the mobile crane 10 and the container yard Y.

As shown in FIG. 1 and FIG. 2, the mobile crane 10 is provided with a gate-shaped crane body 11 that straddles a storage region for storing containers 100 and
a power feed trolley 13 that receives electrical power for operating the mobile crane 10 from a trolley line portion 12 described below.

The crane body 11 has a tire-type travel unit 14, a frame 17 that is constituted in a gate shape by a beam portion 16 that is suspended across the upper ends of a leg portion 15 and a leg portion 15 that are erected in an approximately parallel manner and having the travel unit 14 provided at the lower end, and a suspending mechanism 18 that is provided on the beam portion 16.

The travel unit 14 is, for each leg portion 15, provided as a pair on both sides in a direction intersecting with the extending direction E - F of the beam portion 16, that is, in a direction approximately agreeing with the extending direction A - B of the travel lane L during lateral travel. The travel unit 14 has travel wheels 14a made of a resin such as rubber. Four travel wheels 14a are provided for each leg of the leg portions 15, so that 16 are provided for one mobile crane 10. In the present embodiment, the rotation speed of the travel wheels 14a and the direction of the travel wheels 14a of the travel unit 14 are controlled by remote operation in the remote operation room 40 described below.

In the crane system 1 of the present embodiment, the mobile crane 10 is designed so as to be capable of traveling on its own in the container yard Y by the travel unit 14, and is capable of traveling so as to cause the mobile crane 10 to move from one travel lane L to another travel lane L.

As shown in FIG. I, the beam portion 16 supports the suspending mechanism 18. A guide rail 16a is provided in the beam portion 16 so that the suspending mechanism 18 is capable of travelling in the extending direction E - F of the beam portion 16. The suspending mechanism 18 operates so as to load and unload containers 100, with electrical power that is received from the power feeding
mechanism 2 serving as the motive power.

The suspending mechanism 18 has a trolley 18a that is capable of travelling along the guide rail 16a of the beam portion 16, a spreader 18b that grasps the container 100, a suspending rope 18c that suspends the spreader 18b from the trolley 18a, a hoisting machine 18d that performs winding up and winding out of the suspending rope 18c, and a suspending mechanism control portion (not illustrated) that controls the operation of the trolley 18a, the spreader 18b, and the hoisting machine 18d.

As shown in FIG. 2, the power feed trolley 13 receives electrical power in order to cause the mobile crane 10 to operate by making contact with electrical supply lines of the trolley line portion 12 while moving along the trolley line portion 12 in the extending direction of the trolley line portion 12.

The power feed trolley 13 is coupled to the leg portion 15 of the crane body 11 by a wire W1 that has flexibility. The wire W1 tows the power feed trolley 13 along the trolley line portion 12 when the mobile crane 10 travels in the travel lane L.

Also, when a lane change is being performed during which the mobile crane 10 is moving from one travel lane L to another travel lane L, it is possible to disconnect the coupling of the wire W1 between the power feed trolley 13 and the crane body 11.

An electrical supply cable CI for supplying electrical power that is supplied from the trolley line portion 12 to the power feed trolley 13 to the travel unit 14 and the suspending mechanism 18 of the mobile crane 10 is coupled to the power feed trolley 13 and the mobile crane 10. Similarly to the wire Wl, it is possible to disconnect the coupling of the electrical supply cable CI between the power feed trolley 13 and the crane
body 11 when a lane change is performed.

Herein below, the power feeding mechanism 2 that is disposed in the container yard Y shall be described.

As shown in FIG. I and FIG. 2, the power feeding mechanism 2 of the present embodiment has a trolley line portion 12 that is arranged on one side (the C side in FIG. 1) in the width direction of the travel lane L in the container yard Y. The power feeding mechanism 2 is provided for each travel lane L in the container yard Y. One power feeding mechanism 2 may also be provided for a plurality of travel lanes L.

The trolley line portion 12 is provided in each travel lane L along the extension direction A - B of the travel lane L. An electrical supply line for supplying electrical power for driving the mobile crane 10 is fixed to the trolley line portion 12. In the present embodiment, the trolley line portion 12 is provided in three steps in the height direction of the power feeding mechanism 2, and three electrical supply lines are provided per one step.

As shown in FIG. 3, the remote operation room 40 is provided in the container yard Y, and is a facility for remotely the operating mobile cranes 10 and monitoring the running state of the mobile cranes 10.

Herein below, the communication system 200 that is provided in the crane system I shall be described.

FIG. 4 is a system configuration drawing that shows the constitution of the communication system 200.

As shown in FIG. 4, the communication system 200 is a communication system that performs communication with 22 mobiles cranes 10 (mobile crane 10-1 to mobile crane 10-22). The communication system 200 is provided, in the remote operating room 40, with remote operation consoles 50-1 to 50-10 and a mobile crane group management system 60.

FIG. 4 shows an example in which the communication system 200 is a star network, but it is not limited thereto, and the communication system 200 may be a bus
network or a ring network.

The remote operation consoles 50-1 to 50-10 and the mobile crane group management system 60 are for example, connected by Ethernet (registered trademark). That is, the remote operation consoles 50-1 to 50-10 are connected to a hub 43, and the mobile crane group management system 60 is connected to the hub 43, whereby it is possible to perform mutual data communication. The hub 43 is also connected to the access points 42-1 to 42-22 described below.

The hub 43 relays data between the remote operation consoles 50-1 to 50-10 and the mobile crane group management system 60, and the access points 42-1 to 42-22. In the present embodiment, the hub 43 may be a simple repeater, but it is preferably a switching hub that has a bridge function that transmits by relaying data to the destination based on a destination address that is included in that data that is transmitted to the hub 43.

As for the remote operation consoles 50-1 to 50-10 of the present embodiment, 10 remote operation consoles having the same constitution are provided. Herein below, a description shall be made using the remote operation console 50-1 as an example, and the description of the remote operation consoles 50-2 to 50-10 shall be omitted.

The remote operation console 50-1 remotely operates the mobile crane 10 to make the mobile crane 10 travel and convey the container 100. In the present embodiment, the remote operation console 50 performs remote operation on the mobile crane 10 that requires annual operation among the plurality of mobile cranes 10 (mobile crane 10-1 to 10-22).

The remote operation console 50-1 is provided with video decoders 44-1 and 45-1, monitors 46-1 and 47-1, a microphone 48-1, and a crane operation computer 49-1.
The video decoder 44-1 is connected to the hub 43. The video decoder 44-1 receives the IP data that is relayed and transmitted by the hub 43, converts a digital video signal described below that is included in this IP data to analog data, and transmits it to the monitor 46-1.

The video decoder 45-1 is connected to the hub 43. The video decoder 45-1, similarly to the video decoder 44-1 described above, receives the IP data that is relayed and transmitted by the hub 43, converts a digital video signal described below that is included in this IP data to analog data, and transmits it to the monitor 47-1. Moreover, the video decoder 45-1 also has a function of a voice encoder. That is, the video decoder 45-1 modulates the voice signal that is input to the microphone 48-1 from analogue voice data to digital voice data, and moreover converts it to IP data and transmits it to the video encoder 31-1.

The monitor 46-1 displays video based on the digital video signal that is decoded to an analog video signal by the video decoder 44-1.

The monitor 47-1 displays video based on the digital video signal that is decoded to an analog video signal by the video decoder 45-1.

As the monitors 46-1 and 47-1, it is possible to adopt a cathode ray tube monitor or an LCD display.

The microphone 48-1 is used for the operator who performs remote operation of the mobile crane 10 at the remote operation console 50-1 to give instructions to a worker who is in the vicinity of the mobile crane 10. The microphone 48-1 is electrically connected to the video decoder 45-1, and thereby an analog voice signal is input from the microphone 48-1 to the video decoder 45-1.

The crane operation computer 49-1 is a computer that is provided with an operation panel for operating the mobile crane 10 and a switch or the like that switches the video that is displayed on the monitors 46-1 and 47-1, and is a remote operation unit for remotely operating the mobile crane 10.

The crane operation computer 49-1 can produce command signals for causing the mobile crane 10 to travel in the travel lane L, for causing the mobile crane 10 to move from one travel lane L to another travel lane L, and moreover for performing cargo conveying of the container 100 by operating the trolley 18a of the mobile crane 10.

Moreover, the crane operation computer 49-1 has a command signal converting portion that converts command signals for remotely operating the mobile crane 10 to IP data that has an IP header that includes the IP address (crane ID) of the mobile crane 10 that is the destination of the command signal. Thereby, the crane operation computer 49-1 can transmit IP data that includes command signals to the mobile crane 10 that is associated by the mobile crane group management system 60 described below.

The mobile crane group management system 60 is a higher-level management system of the crane operation computers 49-1 to 49-10 that are provided in the remote operation consoles 50-1 to 50-10, and based on remote operation requests that are transmitted from control computers 33-1 to 33-22 described below that are provided in the mobile cranes 10-1 to 10-22, it selects a remote operation console in a vacant state from the remote operation consoles 50-1 to 50-10, and associates the remote operation console and a mobile crane.

A cargo loading schedule of the containers 100 in the container yard Y is stored in the mobile crane group management system 60. The mobile crane group management system 60 transmits automatic running signals for performing automatic running to the mobile cranes 10-1 to 10-22 based on the cargo loading schedule of the containers 100.
As shown in FIG. 3 and FIG. 4, the communication system 200 is provided with leakage coaxial cables 41-1 to 41-22 and wireless access points 42-1 to 42-22 in the container yard Y.

The leakage coaxial cables 41-1 to 41-22 are 22 leakage coaxial cables having the same constitution. Also, the wireless access points 42-1 to 42-22 are 22 wireless access points having the same constitution. Herein below, a description shall be given using the leakage coaxial cable 41-1 and the wireless access point 42-1 as an example, and the description of the leakage coaxial cables 41-2 to 41-22 and the wireless access points 42-2 to 42-22 shall be omitted.

The leakage coaxial cable 41-1 is a coaxial cable that transmits a high-frequency signal, with an insulator being sheathed on the outer periphery of a core material that consists of a conductor, and a shield material having a plurality of slits that penetrate in the thickness direction being further sheathed on the outer periphery of the insulator. The leakage coaxial cable 41-I as a whole functions as an antenna by a portion of the high-frequency signal that is being transmitted in the core passing through the slits and being propagated to the outside of the leakage coaxial cable 41-1.

As shown in FIG. 2, the leakage coaxial cable 41-1 is fixed to the trolley line portion 12. As shown in FIG. 3, the leakage coaxial cable 41-1 extends along the extension direction of the trolley line portion 12.

In the present embodiment, the rage in which radio waves emitted from the leakage coaxial cable 41-1 reach is inside an approximately cylindrical space in which the center axis line heads in the extension direction of the trolley line portion 12 centered on the leakage coaxial cable 41-1. The radio waves that propagate from the leakage coaxial cable 41-1 reach from the leakage coaxial cable 41-1 to a wireless client antenna 28-1 described below.

The range of the reach of radio waves emitted from the Leal cage coaxial cable 41-1 is preferably a range that is shorter than the overall width of the travel lane L. In this case, since radio wave interference between adjacent travel lanes L is reduced, it is possible to suppress a drop in the transmission rate between the leakage coaxial cable 41-1 and the wireless client antenna 28-1.

The wireless access point 42-1 is electrically connected to the leakage coaxial cable 41-1 and the hub 43. The wireless access point 42-1 of the present embodiment converts IP data that is relayed by the hub 43 and transmitted to the wireless access point 42-1 to a wireless LAN signal in the 2.4 GHz band, and transmits it to the leakage coaxial cable 41-1. The wireless access point 42-1 may for example be an access point that corresponds to wireless LAN of the 5 GHz band conforming to the IEEE 802.1 la standard, and may also be another wireless transmission format.

In the present embodiment, the same channels are assigned to the wireless access points 42-1 to 42-22. For this reason, even if a mobile crane 10 in the container yard Y moves from one travel lane L to a different travel lane L, the mobile crane 10 and the wireless access points 42-1 to 42-22 can continuously communicate using the same wireless communication channels.

Moreover, as shown in FIG. 4, the communication system 200 is provided with a wireless client antenna 28-1, a hub 29-1, video encoders 30-1 and 31-1, a control computer 33, cameras 34-1 and 35-1, and a loudspeaker 37-1 in the mobile crane 10-1.

The wireless client antenna, the hub, the video encoders, the control computer, the camera, and the loudspeaker are provided for each of the mobile cranes 10-1 to 10-22.
Herein below, a description shall be given for the mobile crane 10-1, and descriptions for the mobile cranes 10-2 to 10-22 shall be omitted.

The wireless client antenna 28-1 that is provided in the mobile crane 10-1 is electrically connected to the hub 29-1 by a signal line 27. As shown in FIG. 2, the wireless client antenna 28-1 is fixed to the power feed trolley 13 that is coupled to the crane body 11 of the mobile crane 10-1. The wireless client antenna 28-1 has an antenna that has flexibility, and in this antenna, a detection region is oriented to the outer periphery surface of the leakage coaxial cable 41-1 from a direction that intersects with the lengthwise direction of the leakage coaxial cable 41-1. The wireless client antenna 28-1 can transmit and receive a wireless signal to/from the leakage coaxial cable 41-1.
As shown in FIG. 4, the hub 29-1 is a switching hub that is connected to the wireless client antenna 28-1, the video encoders 30-1 and 31-1, and the control computer 33-1. The hub 29-1 relays data between the video encoders 30-1 and 31-1, and the control computer 33-1 and wireless client antenna 28-1.

The video encoder 30-1 is connected to the hub 29-1. The video encoder 30-1 is a converter that, after converting the video footage shot by the camera 34-1 to a digital video signal, transmits this digital video signal as IP data to any of the video decoders 44-1 to 44-10.

The video encoder 31-1 is connected to the hub 29-1. The video encoder 31-1 is a converter that, after converting the video captured by the camera 35-1 to a digital video signal, transmits this digital video signal as IP data to any of the video decoders 45-1 to 45-10. In the present embodiment, the video encoder 31-1 also has a function of a voice decoder, and converts to an analog signal voice information that has been input to the microphones 48-1 to 48-10 arranged in the remote operation room 40 and converted to IP data by the voice decoder, and transmits it to the loudspeaker 37-1.

The control computer 33-1 is a computer for controlling the travel and the cargo
conveying operations of the mobile crane 10-1.

The control computer 33-1 can transmit a driving signal for operating the travel unit 14 and the suspending mechanism 18 of the mobile crane 10-1 based on an automatic running signal that is transmitted from the mobile crane group management system 60 based on the cargo schedule, and a command signal and the like transmitted from the crane operation computers 49-1 to 49-10 of the remote operation consoles 50-1 to 50-10.
The control computer 33-1 can transmit to the mobile crane group management system 60 a remote operation request for switching to remote operation by manual procedure, in the case of not being able to stack containers within the required accuracy for whatever reason. The remote operation request that is transmitted from the control computer 33-1 is IP data in which the destination address is set to the IP address of the mobile crane group management system 60.

The camera 34-1 is a camera that monitors the suspended state of the container 100 that is held by the spreader 18b of the mobile crane 10-1, as shown in FIG. 3. The camera 34-1 is fixed to the spreader 18b of the mobile crane 10-1. As shown in FIG. 4, the camera 34-1 is connected to the video encoder 30-1.

The camera 35-1 is a camera that reflects the situation under the trolley 18a of the mobile crane 10-1, as shown in FIG. 3. The camera 35-1 is fixed to the trolley 18a of the mobile crane l0-I. As shown in FIG. 4, the camera 35-1 is connected to the video encoder 31-1.
The loudspeaker 37-1 is fixed to the crane body 11 of the mobile crane 10-1. Moreover, the loudspeaker 37-1 is electrically connected to the video encoder 31-1, and a voice that is inputted into any of the microphones 48-1 to 48-10 that are provided in the remote operation consoles 50-1 to 50-10 of the remote operation room 40 is output
from the loudspeaker 37-1.

Herein below, the communication format in the communication system 200 of the present embodiment shall be explained.

As shown in FIGS. 2 and 3, the communication system 200 is a system that receives a detection signal for monitoring in the remote operation room 40 the running state in which the mobile crane that is arranged in the container yard Y automatically travels within the travel lane L and conveys the container 100, and transmits a command signal for operating the travel crane 10 in the remote operation room 40.

In the present embodiment, a signal for monitoring the state of the mobile crane 10 traveling in the travel lane L is a detection signal such as a video signal that is based on video footage shot by a camera provided on the mobile crane 10 (for example, the cameras 34-1 and 35-1, refer to FIG 3), and a signal that is transmitted from a control computer that is provided on the mobile crane 10 (for example, the control computer 33-1, refer to FIG. 4).

In the present embodiment, a command signal for operating the mobile crane 10 in the remote operation room 40 is a control signal that is transmitted from the remote operation room 40 in order to control the operation of the travel unit 14 or the trolley 18a of the mobile crane 10, or a voice signal in which the operator who remotely operates the mobile crane 10 in the remote operation room 40 transmits a voice for giving instructions to the worker in the vicinity of the mobile crane 10 (for example, the driver of the trailer conveying the container 100).
The data that is transmitted and received by the communication system 200 of the present embodiment is IP data in which the transmission source and destination are decided by IP addresses. Individual IP addresses are assigned to all devices that are connected to the communication system 200.

The IP addresses that are assigned to the control computers 33-1 through 33-22 that are provided in the mobile cranes 10-1 through 10-22 function as crane IDs for identifying the mobile cranes 10-1 through 10-22.

Communication is performed between the devices that are connected to the communication system 200 on an Ethernet (registered trademark) network using IP data that has IP headers including the IP addresses of the transmission destination and the IP addresses of the transmission source. The IP addresses that are used in the communication system 200 are preferably local IP addresses. Specifying devices by global IP address in the communication system 200 is also allowed.

The cameras 34-1 and 35-1 transmit video that has been shot as for example an NTSC analog video signal. The video encoders 30-1 and 31-1 that are electrically connected with the cameras 34-1 and 35-1 encode the analog video signals that have been transmitted from the cameras 34-1 and 35-1, respectively, into digital video signals such as MPEG-1, MPEG-2, MPEG-3, MPEG-4 or Motion JPEG.

The digital video signals that have been encoded in the video encoders 30-1 and 31-1 are divided into IP packets (IP datagrams) by the video encoders 30-1 and 31-1, and are converted to IP data in which an IP header that includes the IP address of the transmission source and the IP address of the transmission destination is added. The destination IP address in the video encoders 30-1 and 31-1 is the IP address of the video decoders 44-1 to 44-10 and the video decoders 45-1 to 45-10, and so the IP data that is generated by the video encoders 30-1 and 31-1 is transmitted to the video decoders 44-1 to 44-10, and the video decoders 45-1 to 45-10.

The video that is shot by the cameras 34-1 and 35-1 that are provided in the mobile crane 10-1 is converted to IP data that includes a digital video signal in the video encoders 30-1 and 31-1, respectively, and is transmitted to the video decoders
44-1 to 44-10 and the video decoders 45-1 to 45-10.

Herein below, a description of one example of the operation of the communication system 200 shall be given, referring to FIG. 5. FIG. 5 is a sequence diagram for describing the operation of the communication system 200. Herein below, the operation of the mobile crane 10-1 will be described, and since the operation of the mobile cranes 10-2 to 10-22 are the same, they shall be omitted.

When the mobile crane 10-1 is traveling in the travel lane L and performing cargo handling and carrying of the container 100, an automatic running signal is transmitted from the mobile crane group management system 60 to the control computer 33-1 (SI). The travel in the travel lane L of the container yard Y and cargo handing/carrying by the mobile crane 10-1 is automatically controlled by the automatic running signal (command signal) that is transmitted from the mobile crane group management system 60.

When the mobile crane 10-1 is storing a container in the container yard Y, there are times when it is not possible to perform stacking with a predetermined accuracy. In such an event, the control computer 33-1 of the mobile crane 10-1 stops the automatic operation of the mobile crane 10-1 and transmits as IP data a remote operation request with the mobile crane group management system 60 serving as the destination (S2).

The mobile crane group management system 60, to which the remote operation request has been transmitted from the control computer 33-1, performs a free state query to the crane operation computers 49-1 to 49-10 of the remote operation consoles 50-1 to 50-10 (S3). A crane operation computer that is not being used for remote operation of a mobile crane 10 among the crane operation computers 49-1 to 49-10 responds to the query of the mobile crane group management system 60 so as to give notice to the mobile crane group management system 60 that it is free (S4). For example, if remote operation of the mobile crane 10 in the remote operation console 50-1 is not being performed, the crane operation computer 49-10 responds to the mobile crane group management system 60, and the remote operation console 50-1 is selected by the mobile crane group management system 60. Thereby, one remote operation console in which remote operation of the mobile cranes 10-1 to 10-22 is not being performed is selected from the remote operation consoles 50-1 to 50-10.

Then, the mobile crane group management system 60 notifies the crane operation computer 49-1 of the information of the mobile crane 10 that is the target of remote operation.

When the information on the mobile crane 10 that is the target of remote operation has been provided from the mobile crane group management system 60, the crane operation computer 49-10 notifies the control computer 33-1 of the notified mobile crane 10 of a link designation that links the crane operation computer 49-1 and the control computer 33-1.

The control computer 33-1 sets the destination IP address of the digital video signal that is set to the video encoders 30-1 and 31-1 to the video decoders 44-1 and 45-1 of the remote operation console 50-1 to which the crane operation computer 49-1 is set.
Then, in the remote operation console 50-1, digital video signals are transmitted from the video encoders 30-1 and 31-1 to the video decoders 44-1 and 45-1 (S5), and video footage that is shot by the cameras 34-1 and 35-1 that are provided on the mobile crane 10-1 is displayed on the monitors 46-1 and 47-1.

Note that the video decoders 44-1 and 45-1 may transmit the digital video signals to the crane operation computer 49-1, and in this case, it is possible to display the video shot by the cameras 34-1 and 35-1 of the mobile crane 10 on a monitor that is not illustrated of the crane operation computer 49-1.

Along with a detection signal such as a signal that is emitted from the position sensor 21 being transmitted from the control computer 33-1 to the crane operation computer, a command signal can be transmitted to the control computer of the mobile crane 10-1 using the crane operation computer 49-1.

The operator who operates the mobile crane 10-1 in the remote operation console 50-1 transmits a command signal to the control computer 33-1 so as to position the container 100 within the desired accuracy using the crane operation computer 49-1 of the remote operation console 50-1 (S6). When the operation of the mobile crane 10-1 is completed, the operator transmits an end signal that ends the remote operation by a manual procedure to the control computer 33-1 (S7). Then, the control computer 33-1 requests cancellation of the remote operation request to the mobile crane group management system 60. The mobile crane group management system 60 again transmits an automatic running signal to the control computer 33-1 (S8). Then, the mobile crane 10-1 is again automatically controlled by the mobile crane group management system 60. Moreover, the association between the remote operation console 50-1 and the mobile crane 10-1 is broken off by the end signal transmission of the crane operation computer 49-1, and the remote operation console 50-1 enters a free state.

When the mobile crane 10-1 is not conveying a container 100, in the case of there being a risk of collision between containers 100, and in the case of a positional shift between the container 100 and the automated guide vehicle being detected, a remote operation request is notified from the control computer 33-1 of the mobile crane 10-1 to the mobile crane group management system 60. Then, any remote operation console among the remote operation consoles 50-1 to 50-10 and the mobile crane 10-1 are associated in the same manner as described above, and the mobile crane 10-1 is remotely operated manually.

In the present embodiment, 10 of the remote operation consoles were provided with respect to the 22 mobile cranes that were provided, but when all 10 of the remote operation consoles are in use, there are times of a remote operation request being newly notified from another mobile crane to the mobile crane group management system 60. In this case, the mobile crane group management system 60 holds the selection of a remote operation console until at least one remote operation console is released. Until a remote operation console is selected by the mobile crane group management system 60, the mobile crane 10 that has given notice of a remote operation request is stopped. When the remote operation console is selected by the mobile crane group management system 60 and the remote operation console for remotely operating the mobile crane is decided, the mobile crane can then be operated by using the selected remote operation console.

As described above, since the crane system 1 that is provided with the communication system 200 of the present embodiment automatically controls the mobile cranes 10 based on the IP addresses that are respectively assigned to the mobile cranes l0-I to 10-22, and, by specifying a mobile crane 10, remotely operates the mobile crane 10 using one remote operation console that is selected from among the remote operation consoles 50-1 to 50-10, there is no need to allocate a different wireless communication channel for each of the mobile cranes 10, and so it is possible to cut down on the required number of wireless communication channels.

Also, since the video signal that is shot by the mobile cranes 10 and the command signal for remotely operating the mobile cranes 10 are transmitted and received after being converted to IP data, it is possible to send and receive a plurality of signals with different destinations with one wireless communication channel. For this reason, it is possible to increase the efficiency of performing communication.

Also, in the communication system 200 of the present embodiment, leakage coaxial cables 41-1 to 41-22 are used in order to perform wireless communication between the mobile cranes 10 and the remote operation room 40, and the leakage coaxial cables 41-1 to 41-22 are fixed to the trolley line portion 12, and the wireless client antennas 28-1 to 28-22 that perform wireless communication with the leakage coaxial cables 41-1 to 41-22 are fixed to the power feed trolley 13.

For this reason, even if the mobile crane 10 meanders in the travel lane L, it is possible to keep the distance between the leakage coaxial cables 41-1 to 41-22 and the wireless client antennas 28-1 to 28-22 constant. As a result, it is possible to reduce the possibility of a drop in the communication speed between the leakage coaxial cables 41-1 to 41-22 and the wireless client antennas 28-1 to 28-22.

Moreover, since it is possible to keep constant the orientation of the wireless client antennas 28-1 to 28-22 to the leakage coaxial cables 41-1 to 41-22, it is possible to suppress interference of the wireless communication by radio waves from adjacent travel lanes L.

Also, since the analog video signals of the video footage that is shot by the cameras 34 and 35 that are provided on the mobile crane 10 are transmitted and received as IP data after being encoded to digital video signals, it is possible to reduce the data amount in the case of transmitting and receiving the digital video signals in a compressed form.

Moreover, by encoding to digital video signals the analog video signals of the video footage that is shot by the cameras 34 and 35 that are provided on the mobile crane 10, it is possible to lessen the deterioration of the video even if the data transmission distance becomes long, compared to the case of transmitting and receiving analog signals.
Hereinabove, the embodiment of the present invention was described in detail referring to the appended drawings, but a specific constitution is not limited to this embodiment, and design modifications within the scope of not departing from the spirit of the present invention are also included.

For example, in the aforementioned embodiment, the example was described of one wireless communication channel being used in the communication system 200, but it is not limited thereto, and it is possible to adopt a constitution that uses two or more wireless communications channels. Even in this case, since interference between the wireless signal that is transmitted from the leakage coaxial cable to the outside and the wireless signal that is transmitted from the leakage coaxial cable that is provided in the adjacent travel lane to the outside is suppressed, it is possible to lessen a drop in the wireless communication speed between the leakage coaxial cable and the wireless client antenna.

Also, in the communication system 200, the width of the frequency band per one channel for performing wireless communication between the leakage coaxial cable and the wireless client antenna is not particularly limited.
Also, the mobile crane described in the aforementioned embodiment may be provided with a self-steering mechanism that automatically steers the travel unit 14 within the container yard Y.

While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other
modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.

We Claim:-

1. A communication system that performs communication between a mobile crane that travels in a lane of a container yard and a remote operation unit for remotely operating the mobile crane by receiving a detection signal that indicates the running state of the mobile crane, comprising:

a converter that converts the detection signal to IP data; a leakage coaxial cable that is provided in the travel lane along the travel direction of the mobile crane in order to transmit and receive the IP data; and

an antenna that is provided on the mobile crane and that transmits and receives the IP data to and from the leakage coaxial cable.

2. The communication system according to claim 1, wherein
the remote operation unit transmits to the mobile crane a command signal that instructs movement of the mobile crane between the mobile crane and the remote operation unit; and

the converter converts the command signal to IP data.

3. The communication system according to claims 1 or 2, wherein
the IP data has a crane ID that identifies the mobile crane; the remote operation unit has an operation console in order to remotely operate the mobile crane corresponding to each of the mobile cranes; and

the remote operation unit, by deciding the operation console based on the crane ID, transmits and receives IP data between the operation console and the mobile crane.

4. The communication system according to any one of claims 1 to 3, wherein the leakage coaxial cable is disposed along a trolley line for feeding electrical power to the mobile crane.

5. The communication system according to claim 4, wherein the antenna is fixed to a power feed trolley that is electrically connected to the trolley line that is coupled to the mobile crane.