  Human demonstrations are important in a range of robotics applications, and
are created with a variety of input methods. However, the design space for
these input methods has not been extensively studied. In this paper, focusing
on demonstrations of hand-scale object manipulation tasks to robot arms with
two-finger grippers, we identify distinct usage paradigms in robotics that
utilize human-to-robot demonstrations, extract abstract features that form a
design space for input methods, and characterize existing input methods as well
as a novel input method that we introduce, the instrumented tongs. We detail
the design specifications for our method and present a user study that compares
it against three common input methods: free-hand manipulation, kinesthetic
guidance, and teleoperation. Study results show that instrumented tongs provide
high quality demonstrations and a positive experience for the demonstrator
while offering good correspondence to the target robot.
