Performance analysis of steady-hand teleoperation versus cooperative manipulation

This paper compares two "steady-hand" type systems. The first is an admittance-controlled, non-backdriveable cooperative manipulation system, in which the robot and the operator simultaneously grasp and manipulate a tool. The second is a pair of haptic interfaces configured for unilateral teleoperation. A recently developed pseudo-admittance control law is applied to the master device, which attenuates the operator's high frequency input and sends a "steadied" reference position to the slave. Using a set of planar targeting tasks with varying indexes of difficulty, we found that operator movement time is similar for these two systems. However, the teleoperated system results in more targeting errors due to the limited stiffness display of the haptic interface. These results indicate that operators interact with the pseudo-admittance system as intended, but inherent physical limitations will limit applicability of this approach.