  The goal of this paper is to develop efficient regrasp algorithms for
single-arm and dual-arm regrasp and compares the performance of single-arm and
dual-arm regrasp by running the two algorithms thousands of times. We focus on
pick-and-place regrasp which reorients an object from one placement to another
by using a sequence of pick-ups and place-downs. After analyzing the simulation
results, we find dual-arm regrasp is not necessarily better than single-arm
regrasp: Dual-arm regrasp is flexible. When the two hands can grasp the object
with good clearance, dual-arm regrasp is better and has higher successful rate
than single-arm regrasp. However, dual-arm regrasp suffers from geometric
constraints caused by the two arms. When the grasps overlap, dual-arm regrasp
is bad. Developers need to sample grasps with high density to reduce
overlapping. This leads to exploded combinatorics in previous methods, but is
possible with the algorithms presented in this paper. Following the results,
practitioners may choose single-arm or dual-arm robots by considering the
object shapes and grasps. Meanwhile, they can reduce overlapping and implement
practical dual-arm regrasp by using the presented algorithms.
