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From: Sergio.Sedas@FAS.RI.CMU.EDU
Newsgroups: mod.ai
Subject: Seminar - Disassembly Expert (CMU)
Message-ID: <8611302222.AA16493@ucbvax.Berkeley.EDU>
Date: Wed, 26-Nov-86 22:29:56 EST
Article-I.D.: ucbvax.8611302222.AA16493
Posted: Wed Nov 26 22:29:56 1986
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Master's Defense
Name: Sergio W. Sedas
Title:Disassembly Expert
Dept: ECE
Date: Dec. 3, 1986
Time: 2:00 DHA219 Engineering Design 
           Research  Center (Demo)
      2:30 DH1102 Chemical Engineering 
           Conference Room (Presentation)


An important part in a redesign for assembly expert is a module which will
autonomously disassemble mechanical objects.  Although disassembly is a task
which is easily performed by human beings, it has been a very difficult task
for computers to perform.  This paper describes an algorithm which mimics
the human experimental approach to disassemble mechanical assemblies.  A
highlight in this approach is the ability to determine when a single part or
a group of parts (subassembly) must be removed.

We have divided the disassembly operation into two basic steps.  The first
step selects a part to remove and identifies which parts whose connections
can not be severed must be removed with it.  The second step, incorporated
in a path planner, attempts to remove the subassembly.  During removal,
obstacles may be added or excluded from the subassembly.

A second contribution is the use of multiple representations for
problem solving.  A number of geometric, connectivity and facilities models
are used simultaneously in both steps of the disassembly.

This algorithm has successfully disassembled a flashlight and a piston.  By
modifying the objective we've managed to remove an object from a closed
drawer and a chosen part from a within a flashlight assembly.