This paper introduces graph-rewriting methodology for robotic task planning
. An approach to represent a high-level task plan in the form of a graph an
d modify it to accommodate various planning strategies is proposed. Explici
tly delineated graph-rewrite rules and their ordered applications are used
to reflect the change in plans by changing the graph topology. A framework
for modeling complex manipulation tasks as interconnection of simpler subta
sks and events connecting them is presented. Using a simple example, it is
demonstrated how various: plans: can dynamically evolve as: a function of e
vents. The advantages of graph-rewriting methodology in task planning, impo
rtance of developing a reusable graph-rewrite rule fibrary for manipulation
tasks, and its connection to low-level control are also outlined in this i
ntroductory paper.