Abstract:
A method for scaling a media storage library is provided, wherein the library comprises a plurality of media storage cells and at least one media picker robot. The method comprises connecting a new physical component to a section of the library. Examples of new components include additional robots, storage cell arrays, media players, as well as connecting a second adjacent library by means of a pass-through mechanism. Control software integrates this new physical component into the function of the library by auditing the content and function of the new component. During the connection and functional integration of the new component, the rest of the library continues its current operations. The method may further comprise defining at least one work zone within the library, wherein robots do not enter the work zone but continue to operate in other areas of the library.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to robotic media storage library systems, and more specifically to a redundant system that includes a plurality of independent robots in the form of robotic pods. 
     2. Background of the Invention 
     The current enterprise class library system contains multiple independent robots for concurrently manipulating multiple media cartridges. The library system comprises an array of media storage cells and media cartridge players. A system of rails is used to guide robotic pods through all of the locations on the array. 
     Scalable library systems typically incorporate additional robotic mechanisms and related electromagnetic hardware to increase the size of a system. Some large systems use “pass through” mechanisms to pass cartridges between individual silos to increase the capacity of the system. Pass through mechanisms are field upgradeable, although the library system must be shut down to allow service personnel inside the enclosure(s) during installation. A silo is a “closed” shape that does not allow for capacity scaling without pass through. 
     Therefore it would be desirable to have a method for expanding library system capacity without disrupting normal library operations. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method for scaling a media storage library, wherein the library comprises a plurality of media storage cells and at least one media picker robot. The method comprises connecting a new physical component to a section of the library. Examples of new components include additional robots, storage cell arrays, media players, as well as connecting a second adjacent library by means of a pass-through mechanism. Control software integrates this new physical component into the function of the library by auditing the content and function of the new component. During the connection and functional integration of the new component, the rest of the library continues its current operations. The method may further comprise defining at least one work zone within the library, wherein robots do not enter the work zone but continue to operate in other areas of the library. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
     FIG. 1 depicts a perspective pictorial diagram illustrating the architecture of a single library storage array in accordance with the present invention; 
     FIG. 2 depicts a pictorial diagram illustrating the addition of an extension array to an existing library system in accordance with the present invention; 
     FIG. 3 depicts a flowchart illustrating the procedure for adding an extension array to an existing library system in accordance with the present invention; 
     FIG. 4 depicts a pictorial diagram illustrating the addition of a new library system to an existing library system in accordance with the present invention; and 
     FIG. 5 depicts a flowchart illustrating the procedure for adding a new library system to an existing library system in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The architecture of the present automated library array  100  is illustrated in FIG.  1  and contains the multiple independent robots  102  to enable the library array  100  to concurrently manipulate multiple media cartridges  105 . The library array  100  comprises a two-dimensional array of media cartridge storage cells  103  and media cartridge players  104  that are mounted in a frame  101 . A system of rails  121 - 126  is used to guide robotic pods  102  through all of the locations in the array, which eliminates the need for any steering or guide mechanisms on board the robotic pods  102 , resulting in a reduction in the mass of the robotic pods  102 . The rail system  121 - 126  also constrains the movement of the robotic pods  102  into horizontal and vertical movements, thereby simplifying the control algorithms for collision avoidance that are required by a typical random moveable object handling system based on horizontal, vertical and diagonal degrees of freedom. The robotic pods  102  contain a moveable carriage that is capable of transporting robotic components, such as media cartridge pickers, bar code reading devices, and other task oriented sub-units, on the storage library rail system. 
     As shown in FIG. 1, the frame  101  is designed to receive a plurality of rows  151 - 154  of media cartridge storage cells  103 , each of which is designed to house a single media cartridge  105 . The media cartridge players  104  are shown in an arbitrary location in a horizontal row  155  at the bottom of the frame  101 , although the library array  100  can incorporate media cartridge players  104  at any location in the frame  101  to optimize performance. The robotic pods  102  are attached to the frame  101  via horizontal guide rails  121 - 126 , which serve to frame the media cartridge storage cells  103  and media cartridge players  104  on the top and bottom sides thereof. FIG. 1 shows an array of media storage cells  103  fully populated with media cartridges  105  of any arbitrary type. The robotic pod guide rails  121 - 126  provide support of the robotic pods  102  in the vertical direction to oppose the force of gravity, and they also provide a meshing surface of suitable design to impart traction in the horizontal direction for motive transport of the robotic pods  102 . The robotic pods  102  each incorporate a drive means for propulsion in the horizontal direction along the guide rails  121 . 
     FIG. 1 also shows a plurality of vertical elevator assemblies  131 - 133  that enable the transfer of the robotic pods  102  in the vertical direction. Multiple vertical elevator assemblies  131 - 133  are shown in FIG. 1 to exemplify the extensibility and redundancy of the invention. Each of the vertical elevator assemblies  131 - 133  comprise a set of vertical rails  142  that extend substantially from the top of the frame  101  to the bottom of the frame  101 . The vertical rails  142  support a plurality of elevator stations  140 , each of which contain short horizontal rail segments  141 A,  141 B that are identical in cross section to the main horizontal guide rails  121 - 126 . The elevator stations  140  are held in suspension by a drive belt  143  which is made to wrap around a drive pulley attached to a vertical drive motor  113  that is located at the top of each elevator assembly  133 . When a vertical displacement is required of any robotic pod  102 , the vertical elevator  140  is scheduled to move in alignment to the appropriate level of rows  151 - 155  to allow transfer of the robotic pod  102  onto the elevator rail section  141 A,  141 B from the pair of horizontal rails  121 - 126  that are juxtaposed and abutting to the elevator rails  141 A,  141 B. Once the robotic pod  102  is located on the elevator station  140 , the drive motor  113  is activated to transport the robotic pod  102  to a selected one of rows  151 - 155  and thence moves on to the pair of horizontal rails  121 - 126  that correspond to the selected row. Elevator assemblies  131 - 133  can carry more than one robotic pod  102  at a time by adding elevator platforms  140  to the elevator assemblies  131 - 133  or by extending the elevator platform length to accommodate multiple robotic pods  102  on a single elevator station  140 . 
     Referring to FIG. 2, a pictorial diagram illustrating the addition of an extension array to an existing library system is depicted in accordance with the present invention. The library system  210  depicted in FIGS. 2A-2D is comprised of several library arrays, similar to array  100  in FIG. 1, which are arranged in banks. The track type architecture used with the storage arrays (depicted in FIG. 1) allows the arrays to be connected within a single library system, wherein “roaming” robots can move between arrays by following connecting tracks, which trace cartridge locations and tape drives within the library system. 
     FIG. 3 depicts a flowchart illustrating the procedure for adding an extension array to an existing library system. The procedure begins by selecting, via an operator control panel, the desired capacity scaling method, which in the present example is the addition of an extension array  220  onto an existing library system  210  (step  301 ). The selection causes the control software to move robots away from the end of the rail location where the extension  220  is being added, and establishes the working space as a “keep-out” zone for the robots (step  302 ). In this way, robots within the existing library system  210  can continue to operate in other areas of the library, without interfering with the addition of the extension array  220 . The operator panel is then used to set the relevant service door to an “open-eminent” state, thus alerting the control software to clear the robots from the work area (step  303 ). 
     A door key is then used to unlock and open the service door (step  304 ). The front cover assembly  211  is removed from the end of the library system  210  where the extension  220  is to be added (step  305 ), and the extension array  220  is added to the existing library system  210  (step  306 ). The robot guide rail segments of the extension array, e.g., rail  230 , are then fit to the guide rails on the existing library, e.g., rail  240 , thus connecting power to all segments (step  307 ). A front cover assembly  221  is placed onto the end of the extension array  220  (step  308 ). Additional robots can then be added as needed before the service door is closed (step  309 ). 
     After the physical components have been connected and the service doors have been closed, the operator panel is used to notify the control software to initiate calibration and audit routine to bring the extension array on line with the preexisting library system (step  310 ). 
     When integrating new silos and arrays into an expansionable library system, specific control algorithms are used to facilitate seamless integration. These control algorithms allow the library system to automatically detect new components and determine which resources are available to the system at any time. The algorithms may rely on meta data, which is an inventory of resources available to an array at any given time and is maintained on a micro basis (short time periods). Examples of meta data include: what data storage devices are located within an array; where the storage arrays are located; and how many robots are presently on the array and where they are located, which can change every few fractions of a second as robots move from one array to another. When adding new components to a library system, it is important to merge and integrate the meta data from the different components. When a component is removed, the meta data is uncoupled. Meta data can be stored in NV-RAM, on a hard drive, or any other type of non-volatile memory storage within the arrays, which can hold its memory without power. 
     By implementing the control algorithms described above, there is no need to shut down the library system  210  in order to add new physical components (i.e. extension  220 ). The host system  210  will automatically detect these new components and incorporate their function and contents into ongoing system operations. 
     Referring to FIG. 4, a pictorial diagram illustrating the addition of a new library system to an existing library system is depicted in accordance with the present invention. FIG. 5 depicts a flowchart illustrating the procedure for adding the new library system. The procedure begins by selecting, via an operator control panel, the desired capacity scaling method, which in the present example is the addition of an adjacent library  410  with a pass-through mechanism  420  (step  501 ). The selection causes the control software to move robots away from the end of the rail location where the adjacent library  410  is to be connected, and establishes the working space as a “keep-out” zone for the robots (step  502 ). In this way, robots within the existing library system  400  can continue to operate in other areas of the library, without interfering with the connection of the adjacent library  410  and the installation of the pass-through mechanism  420 . The new library system  410  is then placed next to the original existing library  400  (step  503 ). 
     The operator panel is then used to set the relevant service door  402  to an “open-eminent” state, thus alerting the control software to clear the robots from the work area (step  504 ). A door key is then used to unlock and open the service door where the pass-through mechanism is going to be placed between the library systems (step  505 ). 
     The operator should remove any robots from the work area where the pass-through mechanism is to be installed (step  506 ). The pass-through cover plates  401  and  411  are removed from the side walls of the libraries, thereby allowing the pass-through mechanism  420  access to both library systems  400  and  401  (step  507 ), and the passthrough mechanism  420  is installed by means of the service doors  402  and  412  of either library (step  508 ). 
     The pass-through mechanism  420  allows cartridges to be passed between the adjacent libraries  400  and  410  by means of a bucket  421 , which is driven about a pivot axis  423  by a motor  422 . 
     The power and control circuits of the new adjacent library  410  are then connected to the cable harness of the mother library  400  (step  509 ). Unlike the addition of an extension array, the connection of adjacent libraries does not require the operator to fit guide rail segments between the adjacent libraries. This is because each library is physically self-contained, except for the pass-through mechanism. 
     Once the libraries  400  and  410  are connected, robots are replaced and/or added as needed and the service doors  402  and  412  are closed (step  510 ). The operator control panel is used to notify the control software to initiate calibration and audit routine to bring the new adjacent library  410  on line with the original mother library system  400  (step  511 ). 
     As with addition of extension arrays, by implementing the control algorithms described above, there is no need to shut down the mother library system  400  in order to add new library  410 . The host system  400  will automatically detect the new library  410  and incorporate its function and contents into ongoing system operations. 
     The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.