A Shared-control Teleoperation Architecture forNonprehensile Object Transportation

This article proposes a shared-control teleoperation
architecture for robot manipulators transporting an object on
a tray. Differently from many existing studies about remotely
operated robots with firm grasping capabilities, we consider the
case in which, in principle, the object can break its contact with
the robot end-effector. The proposed shared-control approach
automatically regulates the remote robot motion commanded by
the user and the end-effector orientation to prevent the object
from sliding over the tray. Furthermore, the human operator
is provided with haptic cues informing about the discrepancy
between the commanded and executed robot motion, which assist
the operator throughout the task execution.
We carried out trajectory tracking experiments employing
an autonomous 7 degree-of-freedom (DoF) manipulator and
compared the results obtained using the proposed approach with
two different control schemes (i.e., constant tray orientation and
no motion adjustment). We also carried out a human-subjects
study involving eighteen participants, in which a 3-DoF haptic
device was used to teleoperate the robot linear motion and display
haptic cues to the operator. In all experiments, the results clearly
show that our control approach outperforms the other solutions
in terms of sliding prevention, robustness, commands tracking,
and user’s preference.