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Teach Mastering Process for an Automated Tape Library

IP.com Disclosure Number: IPCOM000105192D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 4 page(s) / 102K

Publishing Venue

IBM

Related People

Chang, P: AUTHOR [+4]

Abstract

The IBM 3495 Tape Library Dataserver (an automated tape library) uses a multiple axis robot mounted on a sled to handle cartridges. Grippers are mounted on the end of the robot arm to pick cartridges. At least one camera is mounted adjacent to the grippers at the end of the robot arm. The entire sled, robot, gripper and camera assembly is referred to as the "accessor".

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Teach Mastering Process for an Automated Tape Library

      The IBM 3495 Tape Library Dataserver (an automated tape
library) uses a multiple axis robot mounted on a sled to handle
cartridges.  Grippers are mounted on the end of the robot arm to pick
cartridges.  At least one camera is mounted adjacent to the grippers
at the end of the robot arm.  The entire sled, robot, gripper and
camera assembly is referred to as the "accessor".

      IBM 3480 Cartridge System Tapes and IBM Enhanced Capacity
Cartridge System Tapes are stored in racks, and the accessor moves
tapes between the racks and IBM 3490 tape drives attached to the
library.

      The camera is attached to a vision system which digitizes the
camera image, and is programmed to analyze the digitized images.  The
camera is used to determine physical gripper positions in the library
by finding fiducial targets mounted in the library, a process
referred to as "teaching" the library.

      An unknown relationship between the gripper and the camera
causes positional errors when teaching the library.  The teach
process uses the camera to locate targets on the system and
determines the appropriate gripper positions to use based on the
camera's position, and therefore requires a known relationship
between the camera and gripper.

      Described is a process to determine the camera to gripper
relationship for all appropriate orientations of robot axes.  This
process is referred to as "teach mastering".  Teach mastering is used
to align the vision system to the gripper on a robot system.

      This process is used on the automated tape library prior to the
library "teach" process.  The automated tape library uses the
accessor to handle cartridges.  In order to accurately grab and place
cartridges to and from racks and 3490 drives, the robot must know
where to place its grippers.

      The teach process assumes that there is a known relationship
between the cameras on the robot and the grippers.  The teach process
uses the camera to predict the locations the grippers should be sent
to.

      The "teach mastering" process is the method used on the
Automated Tape Library to determine the correct relationship between
the camera and grippers.  A number of factors can combine to affect
this relationship:

o   Robot non-linearity

o   Gripper/camera mounting manufacturing variations
o   Gripper/camera Assembly variations
o   Camera alignment variations

      These factors mean that the relationship between the camera and
the grippers can be affected by the orientation of the various robot
axes.  The "teach mastering" process provides a means of determining
the relationships without having to determine the underlying
mechanisms.

      The "teach mastering" process us...