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Detecting Robots Position in a Multiple Robot Library

IP.com Disclosure Number: IPCOM000113618D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Kishi, GT: AUTHOR [+3]

Abstract

In a multiple accessor library, moving an inoperable accessor out of the way is required to keep the library functioning with the other accessors. In such a library each accessor (robot) should have the ability to access each cartridge in the library. If one of the accessors fails the other accessor needs to push it out of the way to be able to access all the cartridges in the library. The failing accessor should be parked in a safe area and must not interfere with the active accessor. Since the accessor has a queue of multiple commands, the host controller will not be a able to detect the exact position of the robot. Detecting the robot position and whether the robot is in an interference position with the rack or any other library component is essential before moving the robot out of the way.

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Detecting Robots Position in a Multiple Robot Library

      In a multiple accessor library, moving an inoperable accessor
out of the way is required to keep the library functioning with the
other accessors.  In such a library each accessor (robot) should have
the ability to access each cartridge in the library.  If one of the
accessors fails the other accessor needs to push it out of the way to
be able to access all the cartridges in the library.  The failing
accessor should be parked in a safe area and must not interfere with
the active accessor.  Since the accessor has a queue of multiple
commands, the host controller will not be a able to detect the exact
position of the robot.  Detecting the robot position and whether the
robot is in an interference position with the rack or any other
library component is essential before moving the robot out of the
way.  In order to move the dead accessor out of the way you need to
know the exact position of the accessor arm.

      This article describes a way for the accessors to talk to each
other and communicate their position for every movement near the
danger or the interface area.  This communication is latched,  when
one of the accessors fail, the other accessors can determine if the
failed accessor can be safely moved.

      The following example describes a two accessor implementation.
This concept can easily be extended to more than two accessors.

      Four latched DI/DO (Digital Input/Digital Output) lines connect
accessor 0 with accessor 1 to detect the arm position in space.

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