Yanxi Liu
"A Computational Representation for Rigid and Articulated Assembly"
1997 International Symposium on Assembly and Task Planning
Abstract
With the increasing level of automation in assembly planning
and assembly execution by machines and robots,
it becomes more obvious that there
is a gap between the output of a mechanical designer and an
assembly planner.
The question is:
How to describe a designed assembly to an assembly planning system?
The input to almost all the current reported automatic assembly planning
systems is one-static-state of the final assembly configuration
regardless the assembly is meant to be rigid or articulated.
The inability to represent the assembly design
completely, accurately and computationally
has hindered the power of an assembly
planner in dealing with articulated assemblies as simple
as taking something out of a drawer.
In this paper we identify a computational representation (specification)
of an assembly.
The basic idea of this representation is simply to use each
{\em oriented} surface on a solid as its primitive feature
and each primitive feature is attached
with its symmetry group. The relative
motions (degree of freedom) under various contacts between
a part or a subassembly and the rest of the assembly can be efficiently
determined by combining these basic symmetry groups in a proved correct
manner.
These results lay out a more realistic and precise group
theoretic framework than our previous work, and
provide a concise, complete and computational
representation for rigid and articulated assembly.