  Existing approaches to direct robot-to-human handovers are typically
implemented on fixed-base robot arms, or on mobile manipulators that come to a
full stop before performing the handover. We propose "on-the-go" handovers
which permit a moving mobile manipulator to hand over an object to a human
without stopping. The on-the-go handover motion is generated with a reactive
controller that allows simultaneous control of the base and the arm. In a user
study, human receivers subjectively assessed on-the-go handovers to be more
efficient, predictable, natural, better timed and safer than handovers that
implemented a "stop-and-deliver" behavior.
