  Shared autonomy teleoperation can guarantee safety, but does so by reducing
the human operator's control authority, which can lead to reduced levels of
human-robot agreement and user satisfaction. This paper presents a novel haptic
shared autonomy teleoperation paradigm that uses haptic feedback to inform the
user about the inner state of a shared autonomy paradigm, while still
guaranteeing safety. This differs from haptic shared control, which uses haptic
feedback to inform the user's actions, but gives the human operator full
control over the robot's actions. We conducted a user study in which twelve
users flew a simulated UAV in a search-and-rescue task with no assistance or
assistance provided by haptic shared control, shared autonomy, or haptic shared
autonomy. All assistive teleoperation methods use control barrier functions to
find a control command that is both safe and as close as possible to the
human-generated control command. For assistive teleoperation conditions with
haptic feedback, we apply a force to the user that is proportional to the
difference between the human-generated control and the safe control. We find
that haptic shared autonomy improves the user's task performance and
satisfaction. We also find that haptic feedback in assistive teleoperation can
improve the user's situational awareness. Finally, results show that adding
haptic feedback to shared-autonomy teleoperation can improve human-robot
agreement.
