The gripper domain was
introduced in the Aips-98
planning competition. The domain concerns a robot with two grippers that must
transport a set of balls from one room to another. In the Aips-98 competition, only Hsp managed to solve the 20 problems.
Figure 20 presents the results in this domain.
Figure 20: Solution length and time
(msecs) in the gripper domain.
Regarding the solution length,
the five planners have been divided into two groups: Grt, Altalt and
Stan produced identical plans of
higher quality, while Ff and Hsp-2 produced identical plans of lower
quality. Regarding solution time, Grt
is the fastest planner in all problems apart from some of the easiest, followed
closely by Stan, next comes Ff, next Altalt and last Hsp-2.
Note that in this domain Stan
takes advantage of its symmetry analysis, which identifies the set of the balls
and the two grippers as symmetric objects (Fox and Long, 1999).
Ioannis
Refanidis
14-8-2001