  Series elastic actuators (SEAs) are interesting for usage in harsh
environments as they are more robust than rigid actuators. This paper shows how
SEAs can be used in teleoperation to increase output velocity in dynamic tasks.
A first experiment is presented that tested human ability to achieve higher
hammerhead velocities with a flexible hammer than with a rigid hammer, and to
evaluate the influence of the resonance frequency. In this experiment, 13
participants executed a hammering task in direct manipulation using flexible
hammers in four conditions with resonance frequencies of 3.0 Hz to 9.9 Hz and
one condition with a rigid hammer. Then, a second experiment is presented that
tested the ability of 32 participants to reproduce the findings of the first
experiment in teleoperated manipulation with different feedback conditions:
with visual and force feedback, without visual feedback, without force
feedback, and with a communication delay of 40 ms. The results indicate that
humans can exploit the mechanical resonance of a flexible system to at least
double the output velocity without combined force and vision feedback. This is
an unexpected result, allowing the design of simpler and more robust
teleoperators for dynamic tasks.
