Patent Publication Number: US-2012043162-A1

Title: Tendon controlled mobile platform

Description:
TECHNICAL FIELD 
     The present invention relates to a tendon-controlled mobile platform, more specifically to a tendon-controlled mobile platform for moving work equipment within a work space defined by a structure such as partition walls of a ship block. 
     BACKGROUND ART 
     The hull of a ship is generally produced by manufacturing units of blocks, which constitute portions of the ship, and then assembling the blocks. That is, after removing the rust or foreign substances from the surface of raw material by use of a method such as blasting and then painting the raw material for the prevention of corrosion, the raw material is made to blocks by, for example, welding, and these blocks are assembled together to complete the hull. 
     Welding, blasting and painting need to be also performed inside each block. Accordingly, various tasks, from collecting the grit used for the blasting to drying the film of paint after the painting to measuring the film of paint, are carried out inside the block. Accordingly, there have been ongoing efforts to develop various kinds of automation equipment for welding, painting, inspection, etc. in order to improve the work efficiency inside the block. 
     The inside of the block is surrounded by structures such as partition walls or shell plates and has a plurality of reinforcing materials, such as longi or stiffner, installed therein in order to reinforce the structural rigidity of the hull. The reinforcing materials are installed to protrude toward the inside of the block. Accordingly, the reinforcing materials interrupt various tasks described above inside the block. 
     Illustrated in  FIG. 1  is an example of an inside of a block of a hull. 
     Referring to  FIG. 1 , an inside of block  10  has a plurality of reinforcing materials  15 ,  16  installed thereon to protrude inwardly. The inside of block  10  can be also partitioned into a plurality of work spaces  11  by a structure such as a partition wall  13 . Formed in the partition wall  13  can be a manhole  17 , which can be used as a path for a worker and through which the worker and work equipment can be moved. 
     Therefore, during the shipbuilding process, workers try to avoid the complex structures of the reinforcing materials  15 ,  16  located on the inside of block  10 , manually move and install automation equipment every time the automation equipment is to be used. Moreover, in order to perform a task on an upper part of the inside of block  10 , a scaffold (not shown) needs to be installed on the inside of block  10 , and the worker needs to stand on the scaffold to perform such task. 
     As such, it requires much time, labor and costs to perform the task while the workers try to avoid the complex structures or install and move the scaffold (not shown) on the inside of block  10 . 
     Particularly, in case automation equipment for welding, painting and inspection on the inside of block  10  is used, the structures such as the reinforcing materials  15 ,  16 , and the scaffold (not shown) installed on the inside of block  10  lower the work efficiency of the automation equipment. 
     Moreover, due to various problems caused by sinking of single hull oil tankers, the International Marine Organization has required since 1996 that all oil tankers be built with a double-hull structure and all LNG carriers be built with a double-hull structure for the safety of the hull. Therefore, the inside of block of a ship has more complicated shapes, making it more difficult to perform the task inside the block. 
     Therefore, there has been a demand for the development of technology that can allow an easier performance of various tasks inside the work space that is defined by the complicated structure such as the inside of block of a ship. 
     DISCLOSURE 
     Technical Problem 
     Contrived to solve the above problem, the present invention allows work equipment to be readily moved in a work space inside a block without being interrupted by reinforcing materials, etc. that are installed inside the block and expands the work area. 
     Technical Solution 
     Contrived to solve the above problem, an aspect of the present invention features a tendon controlled mobile platform configured to move within a work space defined by a structure, including: a mobile platform comprising a main frame, a plurality of upper winches coupled to an upper part of the main frame, and a plurality of lower winches coupled to a lower part of the main frame, the mobile platform being placed with the work space; a plurality of first wires having respective one ends coupled to lower sides of the structure and respective the other ends coupled to the upper winches, the lengths of the first wires being adjustable; and a plurality of second wires having respective one ends coupled to upper sides of the structure and respective the other ends coupled to the lower winches, the lengths of the second wires being adjustable. 
     The plurality of upper winches and the plurality of lower winches can be arranged at locations that are separated from one another, when viewed from a perpendicular direction of a plane that separates the upper part of the main frame from the lower part of the main frame. The tendon controlled mobile platform can include four upper winches and four lower winches, and the four upper winches and the four lower winches can be arranged to form respective rectangles on the plane that separates the upper part of the main frame from the lower part of the main frame, and any pair of facing sides of the rectangle formed by the four lower winches can be shorter than any pair of facing sides of the rectangle formed by the four upper winches. 
     The tendon controlled mobile platform can also include guide rails coupled to the main frame and configured to guide work equipment. The guide rails can include a plurality of guide bars that are parallel to one another, and the plurality of guide bars can be supported by a plurality of supporters protruded from the main frame. A cross-section of each of the plurality of guide bars can have the shape of a rectangle with one side open, and opened sides can face one another. Each of the plurality of guide bars can have a rack gear arranged or formed therein along a lengthwise direction, and the work equipment can include a plurality of pinion gears engaged with the plurality of rack gears. The work equipment can also include a plurality of rollers having linear contact with the guide rails. 
     Advantageous Effects 
     The tendon controlled mobile platform in accordance with the present invention can easily move the mobile platform mounted with the work equipment to a desired location within the work space, allowing various tasks to be carried out efficiently without being hindered by obstacles such as reinforcing materials installed inside a block, and can fully automate the tasks, thereby saving the cost and time required for the tasks. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of an example of a work space inside a block of a ship. 
         FIG. 2  is a perspective view briefly showing a tendon controlled mobile platform in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view showing a mobile platform of the tendon controlled mobile platform in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view showing transporting of work equipment to an adjacent work space using the tendon controlled mobile platform in accordance with an embodiment of the present invention. 
         FIG. 5  is a side view briefly showing an example of comparison for describing a wire connection method of the tendon controlled mobile platform in accordance with an embodiment of the present invention. 
         FIG. 6  is a side view briefly showing the tendon controlled mobile platform in accordance with an embodiment of the present invention. 
         FIG. 7  is a front view of an example of work equipment mounted on the mobile platform shown in  FIG. 3 . 
         FIG. 8  is an enlarged view of the portion marked “A” in  FIG. 7 . 
     
    
    
     MODE FOR INVENTION 
     Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Any identical or corresponding elements will be assigned with identical reference numerals, and they will not be described redundantly. Moreover, a block constituting the hull of a ship will be described as an example of a work space in which a tendon controlled mobile platform in accordance with the present invention is used. 
       FIG. 2  shows work equipment mounted on a tendon controlled mobile platform in accordance with an embodiment of the present invention. 
     Referring to  FIG. 2 , the tendon controlled mobile platform in accordance with an embodiment of the present invention that includes a mobile platform  100 , a first wire  510  and a second wire  520  is installed in a work space  11  on an inside of block  10 , and work equipment  300  is mounted on the tendon controlled mobile platform  100 . 
     Connected respectively to a plurality of upper winches  111  installed in the mobile platform  100  are the other ends of a plurality of the first wires  510 , which are coupled to a lower side of a structure having one end thereof defining the work space. Moreover, connected respectively to a plurality of lower winches  113  are the other ends of a plurality of the second wires  520 , which are coupled to an upper side of the structure. 
     Here, the structure refers to, for example, a partition wall (see reference numeral  13  in  FIG. 1 ) or a reinforcing material (see reference numerals  15  and  16  in  FIG. 1 ), which is located in a boundary area of a work space (see reference numeral  11  of  FIG. 1 ). 
     The plurality of upper winches  111  wind or unwind the plurality of first wires  510  to adjust the length of the first wires  510 , and the plurality of lower winches  113  wind or unwind the plurality of second wires  520  to adjust the length of the second wires  520 . By adjusting the lengths of the plurality of first wires  510  and the plurality of second wires  520 , the location of the mobile platform  100  inside the work space  11  is changed. Therefore, by controlling the plurality of upper winches  111  and the plurality of lower winches  113 , the mobile platform  100  can be moved to a desired location in the work space  11 . 
     As the mobile platform  100  moves in a floated manner within the work space  11 , movement of the mobile platform  100  is not interrupted by the reinforcing materials  15 ,  16 . Particularly, since the mobile platform  100  can be moved to a target location in a shortest route, the time required for moving can be minimized 
     The work equipment  300  can be equipment that performs various required tasks, for example, welding, blasting, painting and surface inspection, within the work space  11 . Therefore, the tendon controlled mobile platform in accordance with an embodiment of the present invention can move the work equipment  300  quickly and easily to a location at which the task needs to be carried out in the work space  11 . 
     The mobile platform  100  will be described in more detain later with reference to  FIG. 3 . 
       FIG. 3  illustrates a mobile platform of the tendon controlled mobile platform in accordance with an embodiment of the present invention. 
     Referring to  FIG. 3 , the mobile platform  100  of the tendon controlled mobile platform in accordance with an embodiment of the present invention includes a main frame  101 , the plurality of upper winches  111  and the plurality of lower winches  113 . 
     The plurality of upper winches  111  are coupled to an upper part of the main frame  101 , and the plurality of lower winches  113  are coupled to a lower part of the main frame  101 . The upper winches  111  and the lower winches  113  are arranged in boundary areas of the main frame  101 . 
     Supposing that there is a plane that divides the main frame  101  into the upper part and the lower part, and viewing the mobile platform  100  from a direction that is perpendicular to the plane, the upper winches  111  and the lower winches  113  are arranged to form apexes of respective rectangles. Here, the rectangle formed by the lower winches  113  has a shorter pair of sides that the rectangle formed by the upper winches  111 . 
     In other words, the lower winches  113  are arranged to be closer toward the center of the main frame  101  than the upper winches  111 . This will be described later in more detail with reference to  FIGS. 5 and 6 . 
     The mobile platform  100  also includes guide rails  150 , which support and guide work equipment (see reference numeral  300  in  FIG. 2 ) mounted in the mobile platform  100 . Here, the guide rails  150  are supported to the main frame  101  by a plurality of supporters  131  that are formed or installed to protrude from the main frame  101 . 
     The guide rails  150  can be installed on both an upper side and a lower side of the main frame  101 , as illustrated, so that the work equipment (see reference numeral  300  of  FIG. 2 ) can be mounted on both an upper side and a lower side of the mobile platform  100 . Moreover, although not illustrated, the guide rails  150  can be installed on lateral sides of the main frame  101 . 
     Here, the guide rails  150  are arranged to be parallel to one another. In the present invention, the term “parallel” refers to the state of being parallel considering errors occurred in the processing and installation, for example, a state of practically being parallel, like a pair of rails that are installed in the railroad. 
     Accordingly, the work equipment  300  can be mounted on the mobile platform  100  by these guide rails  150 , and can be supported and guided by the guide rails  150  to move along a lengthwise direction of the guide rails  150 . 
     After completing the task in the work space  11  of the inside of block  10  using the work equipment  300 , the work equipment  300  needs to be moved to another work space (not shown). The moving of the work equipment  300  will be described with reference to  FIG. 4 . 
     Illustrated in  FIG. 4  is a perspective view of moving the work equipment to an adjacent work space using the tendon controlled mobile platform in accordance with an embodiment of the present invention. This will be described with reference to  FIG. 1  as well. 
     Referring to  FIG. 4 , the work equipment  300  mounted on the mobile platform  100  of the tendon controlled mobile platform in accordance with an embodiment of the present invention can be moved to a mobile platform  100   a  installed in another, adjacent work space (not shown) through a manhole  17 . In other words, after the task to be carried out within the work space  11  of the inside of block  10  is completed, the work equipment  300  can be moved to another work space to continue the task. 
     Therefore, one end of the mobile platform  100  should be able to make contact with another mobile platform  100   a  placed in another, adjacent block (not shown) through the manhole  17 , and the work equipment  300  should be able to move from the mobile platform  100  to the other mobile platform  100   a . For this, one end of the mobile platform  100  should be able to dock with the other mobile platform  100   a , and thus the mobile platform  100  should be able to move to the manhole  17  and the other mobile platform  100   a  should be also able to move to the manhole  17 . Moving the mobile platform  100  to the boundary of the work space  11  will be described later in more detail with reference to  FIGS. 5 and 6 . 
       FIG. 5  shows an example of comparison for describing a wire connection method of the tendon controlled mobile platform in accordance with an embodiment of the present invention, and  FIG. 6  is a side view briefly showing the tendon controlled mobile platform in accordance with an embodiment of the present invention. 
     Referring to  FIG. 5 , the other ends of wires  500   a ,  500   b , of which one ends thereof are coupled to a structure defining the work space  11  of the inside of block  10 , are respectively connected to a plurality of winches  110   a ,  110   b  installed in a mobile platform  100   b.    
     Here, the plurality of wires  500   a ,  500   b  are respectively connected to the winches  110   a ,  110   b  that are closest to the other ends of the wires  500   a ,  500   b , which are coupled to the structure. 
     That is, as illustrated, the other end of the wire  500   a  having one end thereof coupled to an upper side of one side of the structure is connected to the winch  110   a  installed in an upper part of one side of the mobile platform  100   b , and the other end of the wire  500   b  having one end thereof coupled to an upper side of the other side of the structure is connected to the winch  110   b  installed in an upper part of the other side of the mobile platform  100   b . Remaining wires  500   c ,  500   d  are also connected to adjacent winches  110   c ,  110   d , respectively. 
     In this example of comparison having this kind of connection structure, the lengths of the wires  500   a ,  500   d  connected to a side of the structure to which the mobile platform  100   b  needs to be approached need to be maximally reduced, in case the mobile platform  100   b  is moved to one side of the work space  11 , especially if the mobile platform  100   b  needs to be moved to a boundary of one side of the work space  11 , as illustrated in  FIG. 4 . 
     A load applied to the mobile platform  100   b  is delivered to the wires  500   a ,  500   b  connected to the upper side of the structure, and the wires  500   a ,  500   d  that become shortened in order to move the mobile platform  100   b  become to have a greater tension. Therefore, in the illustrated case, the wire  500   a  coupled to the upper side of one side of the structure has the maximum tension. 
     Here, the closer the mobile platform  100   b  moves toward one side of the structure, the greater tension the wire  500   a  has. Also, in order to maintain the mobile platform in level, the wire  500   b  coupled to the upper side of the other side of the structure also becomes to have certain tension. Therefore, no matter how much tension the wire  500   a  has, a horizontal component force is applied to the mobile platform  100   b  by the wire  500   b , making it difficult for the mobile platform  100   b  to reach the manhole  17  located at the boundary of the work space  11 . 
     In order to solve the above problem, it is possible to cross the wires, and this will be described with reference to  FIG. 6 . 
     Referring to  FIG. 6 , the first wire  510  and the second wire  520  are respectively connected to the upper winch  111  and the lower winch  113  in a crossing manner. 
     Specifically, the other end of a second wire  520   a  coupled to the upper side of one side of the structure defining the work space  11  of the inside of block  10  and the other end of a first wire  510   a  coupled to the lower side of one side of the structure are respectively connected a lower winch  113   a  and an upper winch  111   a  installed on one side of the mobile platform  100 . Likewise, the other end of a second wire  520   b  coupled to the upper side of the other side of the structure and the other end of a first wire  510   b  coupled to the lower side of the other side of the structure are respectively connected to a lower winch  113   b  and an upper winch  111   b  installed on the other side of the mobile platform  100 . 
     Here, as illustrated, in case the mobile platform  100  is moved to the boundary of one side of the work space  11 , the lengths of the first wire  510   a  on one side and the second wire  520   a  on one side are maximally reduced. 
     Here, in order to maintain the mobile platform  100  in level, the second wire  520   b  on the other side is tightened to keep the other side of the mobile platform  100  from moving downward. However, if tension is given to the second wire  520   b  on the other side, horizontal force toward the boundary on the other side of the work space  11  is exerted to the mobile platform  100 , inhibiting the mobile platform  100  from moving to the boundary on one side of the work space  11 . 
     Here, if tension is given to the first wire  510   a  on one side, horizontal force moving the mobile platform  100  toward the boundary on one side of the work space  11  and vertical force moving one side of the mobile platform  100  downward are exerted to the mobile platform  100 . 
     The vertical force moving one side of the mobile platform  100  downward works as moment about the lower winch  113   a  installed on one side because the lower winch  113   a  installed on one side is supported by the second wire  520   a  on one side not move downward, thereby working as a force lifting the other side of the mobile platform  100 . 
     Therefore, the tension given to the second wire  520   b  on the other side can be reduced, and thus the horizontal force exerted to the mobile platform  100  toward the other side of the work space  11  by the second wire  520   b  on the other side can be reduced. Moreover, the mobile platform  100  can be easily moved toward one side of the work space  11  by the horizontal force exerted to the mobile platform  100  toward one side of the work space  11  by the first wire  510   a  on one side. 
     Meanwhile, horizontal force toward one side of the work space  11  is also exerted to the mobile platform  100  by the second wire  520   a  on one side, thereby allowing the mobile platform  100  to move to the boundary on one side of the work space  11 . 
     Accordingly, as the tension for keeping the mobile platform  100  in level is dispersed to the first wire  510   a  on one side and the second wire  520   b  on the other side, the moving range of the mobile platform  100  can be increased. 
     As described above, moving the mobile platform  100  to the boundary on one side of the work space  11  requires use of the moment applied to the mobile platform  100  about the lower winch  113   a  on one side by the first wire  510   a  on one side. In order to utilize such moment, the upper winches  111  and the lower winches  113  need to be spaced from one another when viewed from a perpendicular direction of the plane that separates the upper part and lower part of the main frame (reference numeral  101  of  FIG. 3 ) of the mobile platform  100 , as described with reference to  FIG. 3 . 
     Here, the optimal distance by which the upper winches  111  and the lower winches  113  are separated when viewed from the perpendicular direction of the plane separating the upper part of the main frame from the lower part can be obtained through experiments or simulation. Although not illustrated, in case the shape of a mobile platform is different from that of the illustrated mobile platform  100 , the optimal distance by which the upper winches  111  and the lower winches  113  are separated also changes, and thus the separated distance can be changed according to the shape of the mobile platform. 
     For reference, as illustrated, in case the mobile platform  100  is moved to the boundary on one side of the work space  11 , the second wire  520   a  on one side becomes to have maximum tension, and thus it is required to use the second wire  520   a  that has a greater allowable tensile strength than the maximum tension. 
     As described above, the moving range of the mobile platform  100  can be expanded by arranging the upper winches  111  and the lower winches  113  at separated locations when viewed from the perpendicular direction of the plane separating the upper part of the main frame (reference numeral  101  of  FIG. 3 ) of the mobile platform  100  from the lower part thereof. Also, as described with reference to  FIG. 4 , the work equipment  300  can be easily moved to the adjacent mobile platform  100   a , thereby completely automating the tasks carried out by the work equipment  300 . 
       FIG. 7  is a front view of an example of work equipment mounted on the mobile platform shown in  FIG. 3 , and  FIG. 8  is an enlarged view of the portion marked “A” in  FIG. 7 . 
     Referring to  FIG. 7 , the work equipment  300  is supported and guided by the pair of guide rails  150 . Here, as illustrated, the work equipment  300  can include a base  301 , which is moveably coupled to the guide rails  150 , and a work robot  310 , which performs the various tasks described above. 
     Referring to  FIG. 8 , the guide rail  150  includes a guide bar  151 , and the guide bar  151  has a plurality of flanges  153 ,  155 , which support and guide the base  301  in vertical directions, installed or integrated therein. Accordingly, the lengthwise cross-section of the guide rails  150  has the shape of a rectangle with one side open, and opened sides  157  are arranged to face each other to support and guide both ends of the base  301 . 
     As described above, the base  301  can be moved along the lengthwise direction of the guide rails  150 , and thus there can be friction between the base  301  and the flanges  153 ,  155 . Moreover, vibrations generated while the work equipment  300  carries out the various tasks can be transferred to the guide rails  150  and cause a noise. 
     Therefore, a plurality of rollers  350 ,  351  are installed on upper and lower sides of the both ends of the base  301  to allow the rollers  350 ,  351  to have linear contact with the flanges  153 ,  155  and support the base  301  so that friction is kept from occurring between the upper and lower sides of the base  301  and the flanges  153 ,  155  or the vibrations are kept from transferring to one another. 
     To allow the work equipment  300  to move along the lengthwise direction of the guide rails  150 , a rack gear  159  can be installed or formed to protrude along a lengthwise direction of the guide bar  151 , and a pinion gear  330  can be installed in the base  301  to be engaged with the rack gear  159  and rotated by a driving device (not shown). 
     Although not illustrated, sprocket wheels can be installed on ether end of the guide rails  150 . Then, by connecting the two sprocket wheels with a chain and coupling a portion of the chain to a portion on either end of the base  301 , the work equipment  300  can be moved along the lengthwise direction of the guide rails  150 . 
     Moreover, although not illustrated, by installing a screw axis along the lengthwise direction of the guide rails  150  and forming a nut part that is penetrated by the screw axis on both ends of the base  301 , or by coupling a nut that is coupled with the screw axis to the base  301 , the work equipment  300  can be moved along the lengthwise direction of the guide rails  150 . 
     There can be other various linear movement apparatuses that can move the work equipment  300  along the lengthwise direction of the guide rails  150 . 
     Meanwhile, when blasting or painting is performed using the work equipment  300 , it is possible that dust or grit is brought in through the opened sides  157  of the guide rails  150 . Therefore, although not illustrated, the opened sides  157  of the guide rails  150  can have a curtain-shaped dust-guard film or a dust-guard brush installed therein. 
     Although a tendon controlled mobile platform in accordance with an embodiment of the present invention has been described, the technical ideas of the present invention are not restricted to the embodiment presented herein, and another embodiment shall be possible by a person of ordinary skill in the art to which the present invention pertains by supplementing, modifying, deleting and adding elements of the present invention within the same scope of the technical ideas, but this shall be also included in the scope of the technical ideas of the present invention.