Artikel,
On the Exploitation of Mechanical Advantage Near Robot Singularities
Informatica, (1994)
Zusammenfassung
Since the earliest days of robotics research when it was recognized
that kinematic singularities physically hamper the free manipulation
of objects in task space, there has been a popular consensus that
singular configurations are unsuitable for practical use and should
be avoided. At best they may be included with the expectation of
gracefully-degraded performance in their vicinity. In this article
we question the validity of such conclusions, citing examples that
show how humans use singularity configurations of their limbs to
gain mechanical advantage, and investigate the possibility of obtaining
similar benefits in robotic systems. It is shown that minimization
of joint torques in redundant systems leads to human-like behavior
that favors singularities, but that stable implementation of such
behavior requires a strategy which gives the robot more autonomy
with respect to timing task execution. Application of such a strategy
to a 2R robot performing static lifting is considered in detail.
